Set link user to current_user on creation

app/graphql/resolvers/create_link.rb

@@ -1,19 +1,20 @@
 class Resolvers::CreateLink < GraphQL::Function
-  # arguments passed as "args"
+  # Arguments passed as "args"
   argument :description, !types.String
   argument :url, !types.String
 
-  # return type from the mutation
+  # Return type from the mutation
   type Types::LinkType
 
-  # the mutation method
+  # The mutation method
   # _obj - is the parent object, which in this case is nil
   # args - are the arguments passed
-  # _ctx - is the GraphQL context
-  def call(_obj, args, _ctx)
+  # ctx - is the GraphQL context
+  def call(_obj, args, ctx)
     Link.create!(
       description: args[:description],
       url: args[:url],
+      user: ctx[:current_user]
     )
   end
 end

app/graphql/types/link_type.rb

@@ -4,4 +4,5 @@
   field :id, !types.ID
   field :url, !types.String
   field :description, !types.String
+  field :postedBy, -> { Types::UserType }, property: :user
 end

app/models/link.rb

@@ -1,2 +1,3 @@
 class Link < ApplicationRecord
+  belongs_to :user
 end

db/migrate/20170803015541_add_user_id_link.rb

@@ -0,0 +1,7 @@
+class AddUserIdLink < ActiveRecord::Migration[5.1]
+  def change
+    change_table :links do |t|
+      t.references :user, foreign_key: true
+    end
+  end
+end

db/schema.rb

@@ -10,13 +10,15 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170801015006) do
+ActiveRecord::Schema.define(version: 20170803015541) do
 
   create_table "links", force: :cascade do |t|
     t.string "url"
     t.text "description"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.integer "user_id"
+    t.index ["user_id"], name: "index_links_on_user_id"
   end
 
   create_table "users", force: :cascade do |t|

test/graphql/resolvers/create_link_test.rb

@@ -2,7 +2,15 @@
 
 class Resolvers::CreateLinkTest < ActiveSupport::TestCase
   def perform(args = {})
-    Resolvers::CreateLink.new.call(nil, args, {})
+    Resolvers::CreateLink.new.call(nil, args, { current_user: @user })
+  end
+
+  setup do
+    @user = User.create!(
+      name: 'test',
+      email: 'email@example.com',
+      password: 'something'
+    )
   end
 
   test 'creating new link' do
@@ -14,5 +22,6 @@ def perform(args = {})
     assert link.persisted?
     assert_equal link.description, 'description'
     assert_equal link.url, 'http://example.com'
+    assert_equal link.user, @user
   end
 end