Remove comments in migration

db/post_migrate/20170215200045_remove_theme_id_from_users.rb

-# See http://doc.gitlab.com/ce/development/migration_style_guide.html
-# for more information on how to write migrations for GitLab.
-
 class RemoveThemeIdFromUsers < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
 
-  # Set this constant to true if this migration requires downtime.
   DOWNTIME = false
 
-  # When a migration requires downtime you **must** uncomment the following
-  # constant and define a short and easy to understand explanation as to why the
-  # migration requires downtime.
-  # DOWNTIME_REASON = ''
-
-  # When using the methods "add_concurrent_index" or "add_column_with_default"
-  # you must disable the use of transactions as these methods can not run in an
-  # existing transaction. When using "add_concurrent_index" make sure that this
-  # method is the _only_ method called in the migration, any other changes
-  # should go in a separate migration. This ensures that upon failure _only_ the
-  # index creation fails and can be retried or reverted easily.
-  #
-  # To disable transactions uncomment the following line and remove these
-  # comments:
-  # disable_ddl_transaction!
-
   def change
     remove_column :users, :theme_id, :integer
   end

db/schema.rb

@@ -580,9 +580,9 @@ ActiveRecord::Schema.define(version: 20170215200045) do
   end
 
   add_index "labels", ["group_id", "project_id", "title"], name: "index_labels_on_group_id_and_project_id_and_title", unique: true, using: :btree
+  add_index "labels", ["type", "project_id"], name: "index_labels_on_type_and_project_id", using: :btree
   add_index "labels", ["project_id"], name: "index_labels_on_project_id", using: :btree
   add_index "labels", ["title"], name: "index_labels_on_title", using: :btree
-  add_index "labels", ["type", "project_id"], name: "index_labels_on_type_and_project_id", using: :btree
 
   create_table "lfs_objects", force: :cascade do |t|
     t.string "oid", null: false