migration to remove old unused invitation columns from users table

db/migrate/20160810230114_cleanup_invitation_columns_from_users.rb

+class CleanupInvitationColumnsFromUsers < ActiveRecord::Migration
+  class User < ActiveRecord::Base
+  end
+
+  def change
+    remove_index :users, column: %i(invitation_service invitation_identifier),
+                 name: :index_users_on_invitation_service_and_invitation_identifier,
+                 unique: true, length: {invitation_service: 64}
+    remove_index :users, column: :invitation_token, name: :index_users_on_invitation_token
+    remove_index :users, column: :email, name: :index_users_on_email, length: 191
+
+    username_not_null
+
+    remove_column :users, :invitation_token, :string, limit: 60
+    remove_column :users, :invitation_sent_at, :datetime
+    remove_column :users, :invitation_service, :string, limit: 127
+    remove_column :users, :invitation_identifier, :string, limit: 127
+    remove_column :users, :invitation_limit, :integer
+    remove_column :users, :invited_by_type, :string
+
+    add_index :users, :email, name: :index_users_on_email, unique: true, length: 191
+
+    drop_invitations_table
+  end
+
+  def username_not_null
+    reversible do |dir|
+      dir.up do
+        User.delete_all(username: nil)
+        change_column :users, :username, :string, null: false
+      end
+
+      dir.down do
+        change_column :users, :username, :string, null: true
+      end
+    end
+  end
+
+  def drop_invitations_table
+    reversible do |dir|
+      dir.up do
+        drop_table :invitations
+      end
+
+      dir.down do
+        create_invitations_table
+      end
+    end
+  end
+
+  def create_invitations_table
+    # rubocop:disable Style/ExtraSpacing
+    create_table :invitations, force: :cascade do |t|
+      t.text     :message,      limit: 65_535
+      t.integer  :sender_id,    limit: 4
+      t.integer  :recipient_id, limit: 4
+      t.integer  :aspect_id,    limit: 4
+      t.datetime :created_at,                                 null: false
+      t.datetime :updated_at,                                 null: false
+      t.string   :service,      limit: 255
+      t.string   :identifier,   limit: 255
+      t.boolean  :admin,                      default: false
+      t.string   :language,     limit: 255,   default: "en"
+    end
+    # rubocop:enable Style/ExtraSpacing
+
+    add_index :invitations, :aspect_id, name: :index_invitations_on_aspect_id, using: :btree
+    add_index :invitations, :recipient_id, name: :index_invitations_on_recipient_id, using: :btree
+    add_index :invitations, :sender_id, name: :index_invitations_on_sender_id, using: :btree
+
+    add_foreign_key :invitations, :users, column: :recipient_id, name: :invitations_recipient_id_fk, on_delete: :cascade
+    add_foreign_key :invitations, :users, column: :sender_id, name: :invitations_sender_id_fk, on_delete: :cascade
+  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: 20160807212443) do
+ActiveRecord::Schema.define(version: 20160810230114) do
 
   create_table "account_deletions", force: :cascade do |t|
     t.string   "diaspora_handle", limit: 255
@@ -178,23 +178,6 @@ ActiveRecord::Schema.define(version: 20160807212443) do
     t.datetime "updated_at",             null: false
   end
 
-  create_table "invitations", force: :cascade do |t|
-    t.text     "message",      limit: 65535
-    t.integer  "sender_id",    limit: 4
-    t.integer  "recipient_id", limit: 4
-    t.integer  "aspect_id",    limit: 4
-    t.datetime "created_at",                                 null: false
-    t.datetime "updated_at",                                 null: false
-    t.string   "service",      limit: 255
-    t.string   "identifier",   limit: 255
-    t.boolean  "admin",                      default: false
-    t.string   "language",     limit: 255,   default: "en"
-  end
-
-  add_index "invitations", ["aspect_id"], name: "index_invitations_on_aspect_id", using: :btree
-  add_index "invitations", ["recipient_id"], name: "index_invitations_on_recipient_id", using: :btree
-  add_index "invitations", ["sender_id"], name: "index_invitations_on_sender_id", using: :btree
-
   create_table "like_signatures", id: false, force: :cascade do |t|
     t.integer "like_id",            limit: 4,     null: false
     t.text    "author_signature",   limit: 65535, null: false
@@ -624,15 +607,13 @@ ActiveRecord::Schema.define(version: 20160807212443) do
   end
 
   create_table "users", force: :cascade do |t|
-    t.string   "username",                           limit: 255
+    t.string   "username",                           limit: 255,                   null: false
     t.text     "serialized_private_key",             limit: 65535
     t.boolean  "getting_started",                                  default: true,  null: false
     t.boolean  "disable_mail",                                     default: false, null: false
     t.string   "language",                           limit: 255
     t.string   "email",                              limit: 255,   default: "",    null: false
     t.string   "encrypted_password",                 limit: 255,   default: "",    null: false
-    t.string   "invitation_token",                   limit: 60
-    t.datetime "invitation_sent_at"
     t.string   "reset_password_token",               limit: 255
     t.datetime "remember_created_at"
     t.integer  "sign_in_count",                      limit: 4,     default: 0
@@ -642,11 +623,7 @@ ActiveRecord::Schema.define(version: 20160807212443) do
     t.string   "last_sign_in_ip",                    limit: 255
     t.datetime "created_at",                                                       null: false
     t.datetime "updated_at",                                                       null: false
-    t.string   "invitation_service",                 limit: 127
-    t.string   "invitation_identifier",              limit: 127
-    t.integer  "invitation_limit",                   limit: 4
     t.integer  "invited_by_id",                      limit: 4
-    t.string   "invited_by_type",                    limit: 255
     t.string   "authentication_token",               limit: 30
     t.string   "unconfirmed_email",                  limit: 255
     t.string   "confirm_email_token",                limit: 30
@@ -669,9 +646,7 @@ ActiveRecord::Schema.define(version: 20160807212443) do
   end
 
   add_index "users", ["authentication_token"], name: "index_users_on_authentication_token", unique: true, using: :btree
-  add_index "users", ["email"], name: "index_users_on_email", length: {"email"=>191}, using: :btree
-  add_index "users", ["invitation_service", "invitation_identifier"], name: "index_users_on_invitation_service_and_invitation_identifier", unique: true, length: {"invitation_service"=>64, "invitation_identifier"=>nil}, using: :btree
-  add_index "users", ["invitation_token"], name: "index_users_on_invitation_token", using: :btree
+  add_index "users", ["email"], name: "index_users_on_email", unique: true, length: {"email"=>191}, using: :btree
   add_index "users", ["username"], name: "index_users_on_username", unique: true, length: {"username"=>191}, using: :btree
 
   add_foreign_key "aspect_memberships", "aspects", name: "aspect_memberships_aspect_id_fk", on_delete: :cascade
@@ -687,8 +662,6 @@ ActiveRecord::Schema.define(version: 20160807212443) do
   add_foreign_key "conversation_visibilities", "people", name: "conversation_visibilities_person_id_fk", on_delete: :cascade
   add_foreign_key "conversations", "people", column: "author_id", name: "conversations_author_id_fk", on_delete: :cascade
   add_foreign_key "id_tokens", "authorizations"
-  add_foreign_key "invitations", "users", column: "recipient_id", name: "invitations_recipient_id_fk", on_delete: :cascade
-  add_foreign_key "invitations", "users", column: "sender_id", name: "invitations_sender_id_fk", on_delete: :cascade
   add_foreign_key "like_signatures", "likes", name: "like_signatures_like_id_fk", on_delete: :cascade
   add_foreign_key "like_signatures", "signature_orders", name: "like_signatures_signature_orders_id_fk"
   add_foreign_key "likes", "people", column: "author_id", name: "likes_author_id_fk", on_delete: :cascade