Add field that references issue this issue has been moved to

app/models/issue.rb

@@ -16,6 +16,7 @@
 #  state         :string(255)
 #  iid           :integer
 #  updated_by_id :integer
+#  moved_to_id   :integer
 #
 
 require 'carrierwave/orm/activerecord'
@@ -31,6 +32,8 @@ class Issue < ActiveRecord::Base
   ActsAsTaggableOn.strict_case_match = true
 
   belongs_to :project
+  belongs_to :moved_to, class_name: 'Issue'
+
   validates :project, presence: true
 
   scope :of_group,

db/migrate/20160317092222_add_moved_to_to_issue.rb

+class AddMovedToToIssue < ActiveRecord::Migration
+  def change
+    add_reference :issues, :moved_to, references: :issues, index: true
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160316123110) do
+ActiveRecord::Schema.define(version: 20160317092222) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -416,6 +416,7 @@ ActiveRecord::Schema.define(version: 20160316123110) do
     t.string   "state"
     t.integer  "iid"
     t.integer  "updated_by_id"
+    t.integer  "moved_to_id"
   end
 
   add_index "issues", ["assignee_id"], name: "index_issues_on_assignee_id", using: :btree
@@ -424,6 +425,7 @@ ActiveRecord::Schema.define(version: 20160316123110) do
   add_index "issues", ["created_at"], name: "index_issues_on_created_at", using: :btree
   add_index "issues", ["description"], name: "index_issues_on_description_trigram", using: :gin, opclasses: {"description"=>"gin_trgm_ops"}
   add_index "issues", ["milestone_id"], name: "index_issues_on_milestone_id", using: :btree
+  add_index "issues", ["moved_to_id"], name: "index_issues_on_moved_to_id", using: :btree
   add_index "issues", ["project_id", "iid"], name: "index_issues_on_project_id_and_iid", unique: true, using: :btree
   add_index "issues", ["project_id"], name: "index_issues_on_project_id", using: :btree
   add_index "issues", ["state"], name: "index_issues_on_state", using: :btree