add mirror specific settings to application settings

db/migrate/20170515093334_add_mirror_settings_to_application_setting.rb

+class AddMirrorSettingsToApplicationSetting < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_column_with_default :application_settings,
+                            :mirror_max_delay,
+                            :integer,
+                            default: 5,
+                            allow_null: false
+
+    add_column_with_default :application_settings,
+                            :mirror_max_capacity,
+                            :integer,
+                            default: 100,
+                            allow_null: false
+
+    add_column_with_default :application_settings,
+                            :mirror_capacity_threshold,
+                            :integer,
+                            default: 50,
+                            allow_null: false
+
+    ApplicationSetting.expire
+  end
+
+  def down
+    remove_column :application_settings, :mirror_max_delay
+    remove_column :application_settings, :mirror_max_capacity
+    remove_column :application_settings, :mirror_capacity_threshold
+  end
+end

db/schema.rb

@@ -137,6 +137,9 @@ ActiveRecord::Schema.define(version: 20170602003304) do
     t.boolean "clientside_sentry_enabled", default: false, null: false
     t.string "clientside_sentry_dsn"
     t.boolean "check_namespace_plan", default: false, null: false
+    t.integer "mirror_max_delay", default: 5, null: false
+    t.integer "mirror_max_capacity", default: 100, null: false
+    t.integer "mirror_capacity_threshold", default: 50, null: false
   end
 
   create_table "approvals", force: :cascade do |t|