Remove timestamps from ci_runner_groups table

db/migrate/20170301101006_add_ci_runner_groups.rb

@@ -9,8 +9,6 @@ class AddCiRunnerGroups < ActiveRecord::Migration
     create_table :ci_runner_groups do |t|
       t.integer :runner_id
       t.integer :group_id
-
-      t.timestamps_with_timezone null: false
     end
 
     add_concurrent_index :ci_runner_groups, :runner_id

db/schema.rb

@@ -446,8 +446,6 @@ ActiveRecord::Schema.define(version: 20180425131009) do
   create_table "ci_runner_groups", force: :cascade do |t|
     t.integer "runner_id"
     t.integer "group_id"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
   end
 
   add_index "ci_runner_groups", ["group_id"], name: "index_ci_runner_groups_on_group_id", using: :btree