use puma instead of thin

Gemfile

@@ -6,7 +6,7 @@ gem 'dotenv-rails', groups: [:development, :test]
 
 gem 'rails', '4.2.3'
 gem 'devise', '~> 3.5.0'
-gem 'thin'
+gem 'puma'
 gem 'jquery-rails'
 gem 'nested_form'
 gem 'select2-rails'

Gemfile.lock

@@ -104,7 +104,6 @@ GEM
     crack (0.4.2)
       safe_yaml (~> 1.0.0)
     crass (1.0.2)
-    daemons (1.2.3)
     debug_inspector (0.0.2)
     devise (3.5.2)
       bcrypt (~> 3.0)
@@ -125,7 +124,6 @@ GEM
     eco-source (1.1.0.rc.1)
     ejs (1.1.1)
     erubis (2.7.0)
-    eventmachine (1.0.8)
     excon (0.45.4)
     execjs (2.6.0)
     factory_girl (4.5.0)
@@ -240,6 +238,7 @@ GEM
       cliver (~> 0.3.1)
       multi_json (~> 1.0)
       websocket-driver (>= 0.2.0)
+    puma (2.13.4)
     quiet_assets (1.1.0)
       railties (>= 3.1, < 5.0)
     rack (1.6.4)
@@ -337,10 +336,6 @@ GEM
     sqlite3 (1.3.10)
     test_after_commit (0.4.1)
       activerecord (>= 3.2)
-    thin (1.6.3)
-      daemons (~> 1.0, >= 1.0.9)
-      eventmachine (~> 1.0)
-      rack (~> 1.0)
     thor (0.19.1)
     thread_safe (0.3.5)
     tilt (1.4.1)
@@ -404,6 +399,7 @@ DEPENDENCIES
   omniauth-twitter
   pg
   poltergeist
+  puma
   quiet_assets
   rack-canonical-host
   rails (= 4.2.3)
@@ -420,7 +416,6 @@ DEPENDENCIES
   simple_form
   sqlite3
   test_after_commit
-  thin
   uglifier
   webmock
 

Procfile

@@ -1 +1 @@
-web: rails server thin -p $PORT -e $RACK_ENV
+web: bundle exec puma -C config/puma.rb

config/database.yml

@@ -26,7 +26,5 @@ test:
   timeout: 5000
 
 production:
-  adapter: sqlite3
-  database: db/production.sqlite3
-  pool: 5
-  timeout: 5000
+  url:  <%= ENV["DATABASE_URL"] %>
+  pool: <%= ENV["DB_POOL"] || ENV['MAX_THREADS'] || 5 %>

config/puma.rb

@@ -0,0 +1,15 @@
+workers Integer(ENV['WEB_CONCURRENCY'] || 2)
+threads_count = Integer(ENV['MAX_THREADS'] || 5)
+threads threads_count, threads_count
+
+preload_app!
+
+rackup      DefaultRackup
+port        ENV['PORT']     || 3000
+environment ENV['RACK_ENV'] || 'development'
+
+on_worker_boot do
+  # Worker specific setup for Rails 4.1+
+  # See: https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#on-worker-boot
+  ActiveRecord::Base.establish_connection
+end