diff --git a/.rubocop.yml b/.rubocop.yml
index a89826970..568f53a0f 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -64,6 +64,9 @@ Rails/Date:
 Rails/Delegate:
   Enabled: false
 
+Bundler/DuplicatedGem:
+  Enabled: false
+
 Rails/Exit:
   Exclude:
     - lib/tasks/support/rspec_rerunner.rb
@@ -71,12 +74,19 @@ Rails/Exit:
 Rails/HasAndBelongsToMany:
   Enabled: false
 
+# TODO: remove in rails 5
+Rails/HttpPositionalArguments:
+  Enabled: false
+
 Rails/Output:
   Enabled: false
 
 Rails/ReadWriteAttribute:
   Enabled: false
 
+Rails/SkipsModelValidations:
+  Enabled: false
+
 Rails/TimeZone:
   Enabled: false
 
diff --git a/app/controllers/events/attendee_names_controller.rb b/app/controllers/events/attendee_names_controller.rb
index 23564deb4..904ffe7ec 100644
--- a/app/controllers/events/attendee_names_controller.rb
+++ b/app/controllers/events/attendee_names_controller.rb
@@ -19,7 +19,7 @@ def index
   private
 
   def find_event
-    @event = Event.find_by_id(params[:event_id])
+    @event = Event.find_by(id: params[:event_id])
   end
 
   def attendee_csv_data(rsvps)
diff --git a/app/controllers/events/attendees_controller.rb b/app/controllers/events/attendees_controller.rb
index 3e09cc717..354189dfc 100644
--- a/app/controllers/events/attendees_controller.rb
+++ b/app/controllers/events/attendees_controller.rb
@@ -25,7 +25,7 @@ def update
   private
 
   def find_event
-    @event = Event.find_by_id(params[:event_id])
+    @event = Event.find_by(id: params[:event_id])
   end
 
   def attendee_csv_data(rsvps)
diff --git a/app/controllers/events/emails_controller.rb b/app/controllers/events/emails_controller.rb
index f6c970416..db5341a23 100644
--- a/app/controllers/events/emails_controller.rb
+++ b/app/controllers/events/emails_controller.rb
@@ -58,7 +58,7 @@ def email_params
     end
 
     def find_event
-      @event = Event.find_by_id(params[:event_id])
+      @event = Event.find_by(id: params[:event_id])
     end
 
     def present_form_data
diff --git a/app/controllers/events/organizer_tools_controller.rb b/app/controllers/events/organizer_tools_controller.rb
index 22c3b50d9..8d1a1db6d 100644
--- a/app/controllers/events/organizer_tools_controller.rb
+++ b/app/controllers/events/organizer_tools_controller.rb
@@ -39,7 +39,7 @@ def diets
 
   def rsvp_preview
     authorize @event, :edit?
-    role = Role.find_by_id(params[:role_id])
+    role = Role.find_by(id: params[:role_id].to_i)
     @rsvp = @event.rsvps.build(role: role)
     @rsvp.setup_for_role(role)
     @rsvp_preview_mode = true
@@ -75,6 +75,6 @@ def send_announcement_email
   private
 
   def find_event
-    @event = Event.find_by_id(params[:event_id])
+    @event = Event.find_by(id: params[:event_id])
   end
 end
diff --git a/app/controllers/events/students_controller.rb b/app/controllers/events/students_controller.rb
index 7cbe0cf16..ef1de00ba 100644
--- a/app/controllers/events/students_controller.rb
+++ b/app/controllers/events/students_controller.rb
@@ -18,7 +18,7 @@ def index
     private
 
     def find_event
-      @event = Event.find_by_id(params[:event_id])
+      @event = Event.find_by(id: params[:event_id])
     end
 
     def student_csv_data(rsvps)
diff --git a/app/controllers/rsvps_controller.rb b/app/controllers/rsvps_controller.rb
index fd2d4a2d7..e6dd85758 100644
--- a/app/controllers/rsvps_controller.rb
+++ b/app/controllers/rsvps_controller.rb
@@ -134,7 +134,7 @@ def rsvp_params
   end
 
   def load_rsvp
-    @rsvp = Rsvp.find_by_id(params[:id])
+    @rsvp = Rsvp.find_by(id: params[:id])
     unless @rsvp && ((@rsvp.user == current_user) || @rsvp.event.organizer?(current_user))
       redirect_to events_path, notice: 'You are not signed up for this event'
     end
@@ -149,7 +149,7 @@ def redirect_if_event_in_past
   end
 
   def assign_event
-    @event = Event.find_by_id(params[:event_id])
+    @event = Event.find_by(id: params[:event_id])
     if @event.nil?
       redirect_to events_path, notice: 'You are not signed up for this event'
     end
diff --git a/app/controllers/sections_controller.rb b/app/controllers/sections_controller.rb
index 1f353272c..61e36430b 100644
--- a/app/controllers/sections_controller.rb
+++ b/app/controllers/sections_controller.rb
@@ -34,7 +34,7 @@ def arrange
   private
 
   def find_event
-    @event = Event.find_by_id(params[:event_id])
+    @event = Event.find_by(id: params[:event_id])
   end
 
   def section_params
diff --git a/app/models/event.rb b/app/models/event.rb
index ecb67c20e..93a122829 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -276,7 +276,7 @@ def organizers_with_legacy
   end
 
   def rsvp_for_user(user)
-    rsvps.find_by_user_id(user.id)
+    rsvps.find_by(user_id: user.id)
   end
 
   def no_rsvp?(user)
diff --git a/config/environments/development.rb b/config/environments/development.rb
index 29455c470..05f5d81eb 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -44,7 +44,7 @@
   # Send to local mailserver for viewing mail with mailcatcher
   config.action_mailer.delivery_method = :smtp
   config.action_mailer.smtp_settings = { address: "localhost", port: 1025 }
-  config.action_mailer.preview_path = "#{Rails.root}/spec/mailers/previews"
+  config.action_mailer.preview_path = Rails.root.join('spec', 'mailers', 'previews')
 
   # Setup default url options for your specific environment.
   config.action_mailer.default_url_options = { host: 'localhost:3000' }
diff --git a/db/migrate/20170110062210_set_id_sequence_for_new_courses.rb b/db/migrate/20170110062210_set_id_sequence_for_new_courses.rb
index 8b7f0dc01..3985875b9 100644
--- a/db/migrate/20170110062210_set_id_sequence_for_new_courses.rb
+++ b/db/migrate/20170110062210_set_id_sequence_for_new_courses.rb
@@ -1,5 +1,5 @@
 class SetIdSequenceForNewCourses < ActiveRecord::Migration
-  def change
+  def up
     if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
       execute("ALTER SEQUENCE courses_id_seq START with 10000 RESTART;")
     else
diff --git a/db/seeds/seed_event.rb b/db/seeds/seed_event.rb
index ba5347af1..46260b60f 100644
--- a/db/seeds/seed_event.rb
+++ b/db/seeds/seed_event.rb
@@ -92,7 +92,7 @@ def self.seed_event(options={})
       title: 'Seeded Test Event',
       student_rsvp_limit: 5,
       time_zone: 'Pacific Time (US & Canada)',
-      course: Course.find_by_name('RAILS'),
+      course: Course.find_by(name: 'RAILS'),
       location: location,
       chapter: chapter,
       current_state: :published,
@@ -182,14 +182,14 @@ def self.seed_event(options={})
       recipient_rsvps: event.volunteer_rsvps
     )
 
-    User.find_by_email('volunteer1@example.com').rsvps.last.create_survey!(
+    User.find_by(email: 'volunteer1@example.com').rsvps.last.create_survey!(
       good_things: 'The textboxes! Boy, I love filling out textboxes!',
       bad_things: 'Too many terminator robots allowed at the workshop',
       other_comments: 'jolly good show, old bean',
       recommendation_likelihood: 7
     )
 
-    User.find_by_email('student1-1@example.com').rsvps.last.create_survey!(
+    User.find_by(email: 'student1-1@example.com').rsvps.last.create_survey!(
       good_things: 'I liked the food and also the learning',
       bad_things: "Volunteers could've tried to do a more interesting dance",
       other_comments: 'pip pip, cheerio',
@@ -231,7 +231,7 @@ def self.seed_multiple_location_event(options={})
       title: 'Seeded Multiple Location Event',
       student_rsvp_limit: 15,
       time_zone: 'Pacific Time (US & Canada)',
-      course: Course.find_by_name("RAILS"),
+      course: Course.find_by(name: "RAILS"),
       location: location,
       chapter: chapter,
       current_state: :published,
diff --git a/lib/tasks/db.rake b/lib/tasks/db.rake
index c067086ee..fc74f2dd3 100644
--- a/lib/tasks/db.rake
+++ b/lib/tasks/db.rake
@@ -4,6 +4,14 @@
 
 Rake::Task["db:schema:dump"].clear
 
+def db_dump_filename(args)
+  if args[:filename]
+    Rails.root.join(args[:filename])
+  else
+    Rails.root.join('db', 'PRODUCTION.dump')
+  end
+end
+
 db_namespace = namespace :db do
   namespace :schema do
     desc 'Create a db/schema.rb file that is portable against any DB supported by AR'
@@ -76,7 +84,7 @@ db_namespace = namespace :db do
 
   desc "Dump current database to a file"
   task :dump, [:filename] => [:environment] do |t, args|
-    filename = Rails.root.join(args[:filename] || 'db/PRODUCTION.dump')
+    filename = db_dump_filename(args)
     cmd = nil
     with_config do |app, host, db|
       cmd = "pg_dump --host #{host} --no-owner --no-acl --format=c #{db} > #{filename}"
@@ -95,7 +103,7 @@ db_namespace = namespace :db do
 
   desc "Restores the database from a dump file"
   task :restore, [:filename] => [:environment, 'db:drop', 'db:create'] do |t, args|
-    filename = Rails.root.join(args[:filename] || 'db/PRODUCTION.dump')
+    filename = db_dump_filename(args)
     cmd = nil
     with_config do |app, host, db|
       cmd = "pg_restore --verbose --host #{host} --clean --no-owner --no-acl --dbname #{db} #{filename}"
diff --git a/spec/controllers/events_controller_spec.rb b/spec/controllers/events_controller_spec.rb
index f8eace485..41a7b2510 100644
--- a/spec/controllers/events_controller_spec.rb
+++ b/spec/controllers/events_controller_spec.rb
@@ -494,7 +494,7 @@ def make_request
 
       it "destroys the event and redirects to the events page" do
         make_request
-        expect(Event.find_by_id(event.id)).to eq(nil)
+        expect(Event.find_by(id: event.id)).to eq(nil)
         expect(response).to redirect_to events_path
       end
     end
diff --git a/spec/controllers/sections_controller_spec.rb b/spec/controllers/sections_controller_spec.rb
index 617c61a01..826321ef4 100644
--- a/spec/controllers/sections_controller_spec.rb
+++ b/spec/controllers/sections_controller_spec.rb
@@ -48,7 +48,7 @@
       expect {
         delete :destroy, event_id: @event.id, id: @section.id
       }.to change(@event.sections, :count).by(-1)
-      expect(Section.find_by_id(@section.id)).to be_nil
+      expect(Section.find_by(id: @section.id)).to be_nil
     end
   end
 
diff --git a/spec/factories.rb b/spec/factories.rb
index 61eea9bcf..71f90f7da 100644
--- a/spec/factories.rb
+++ b/spec/factories.rb
@@ -121,7 +121,7 @@
   factory :rsvp, aliases: [:volunteer_rsvp] do
     user
     event
-    role Role.find_by_title('Volunteer')
+    role Role.find_by(title: 'Volunteer')
     teaching_experience "Quite experienced"
     subject_experience "Use professionally"
     childcare_info "Bobby: 8\nSusie: 4"
@@ -129,7 +129,7 @@
     dietary_info "Paleo"
 
     factory :student_rsvp do
-      role Role.find_by_title 'Student'
+      role Role.find_by title: 'Student'
       operating_system OperatingSystem::OSX_LION
       class_level 2
     end
@@ -141,7 +141,7 @@
     end
 
     factory :organizer_rsvp do
-      role Role.find_by_title 'Organizer'
+      role Role.find_by title: 'Organizer'
     end
     transient do
       session_checkins nil
diff --git a/spec/features/events/event_listing_request_spec.rb b/spec/features/events/event_listing_request_spec.rb
index 1b67f2e16..1940f8ec6 100644
--- a/spec/features/events/event_listing_request_spec.rb
+++ b/spec/features/events/event_listing_request_spec.rb
@@ -160,7 +160,7 @@
         expect(page).to have_content good_event_title
         expect(page).to have_content("My Amazing Session")
         expect(page).to have_content("This event currently has no location!")
-        expect(page).to have_content(Course.find_by_name('RAILS').description.split('.')[0])
+        expect(page).to have_content(Course.find_by(name: 'RAILS').description.split('.')[0])
 
         visit events_path
 
@@ -316,7 +316,7 @@
 
         it "allows user to cancel their event RSVP" do
           click_link('Cancel RSVP')
-          expect(Rsvp.find_by_id(@rsvp.id)).to be_nil
+          expect(Rsvp.find_by(id: @rsvp.id)).to be_nil
         end
 
         it "allows user to edit volunteer responsibilities" do
diff --git a/spec/mailers/mailer_previews_spec.rb b/spec/mailers/mailer_previews_spec.rb
index e0814f69c..58e54cc44 100644
--- a/spec/mailers/mailer_previews_spec.rb
+++ b/spec/mailers/mailer_previews_spec.rb
@@ -1,8 +1,8 @@
 require 'rails_helper'
 
 require Rails.root.join('db', 'seeds', 'seed_event')
-Dir[Rails.root.join("app/mailers/*.rb")].each { |f| require f }
-Dir[Rails.root.join("spec/mailers/previews/**/*.rb")].each { |f| require f }
+Dir[Rails.root.join("app", "mailers", "*.rb")].each { |f| require f }
+Dir[Rails.root.join("spec", "mailers", "previews", "**", "*.rb")].each { |f| require f }
 
 RSpec.describe 'mailer previews' do
   def find_preview_class(mailer_class)
diff --git a/spec/models/event_spec.rb b/spec/models/event_spec.rb
index fc9a9dbe3..ab7a78451 100644
--- a/spec/models/event_spec.rb
+++ b/spec/models/event_spec.rb
@@ -227,7 +227,7 @@
   describe "#rsvp_for_user" do
     it "should return the rsvp for a user" do
       event = create(:event)
-      expect(event.rsvp_for_user(@user)).to eq(event.rsvps.find_by_user_id(@user.id))
+      expect(event.rsvp_for_user(@user)).to eq(event.rsvps.find_by(user_id: @user.id))
     end
   end
 
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index bdb56cd69..d0fb3526b 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -18,7 +18,7 @@
     rsvp = create(:rsvp, event_id: event.id, user: user)
 
     user.destroy
-    expect(Rsvp.find_by_id(rsvp.id)).to be_nil
+    expect(Rsvp.find_by(id: rsvp.id)).to be_nil
   end
 
   it 'can update the profile via nested attributes' do
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index 0b0ca8979..b0294ed08 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -21,7 +21,7 @@
 
 Capybara.asset_host = "http://#{Rails.application.routes.default_url_options[:host]}"
 
-Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}
+Dir[Rails.root.join("spec", "support", "**", "*.rb")].each {|f| require f}
 
 Shoulda::Matchers.configure do |config|
   config.integrate do |with|
diff --git a/spec/seeds/seeds_spec.rb b/spec/seeds/seeds_spec.rb
index aff901a6a..d4fc17f0c 100644
--- a/spec/seeds/seeds_spec.rb
+++ b/spec/seeds/seeds_spec.rb
@@ -29,7 +29,7 @@
     event.organizers << innocent_user
 
     Seeder.destroy_event(event)
-    expect(User.find_by_id(innocent_user.id)).to be_present
+    expect(User.find_by(id: innocent_user.id)).to be_present
   end
 end