Remove unnecessary index_projects_on_builds_enabled index from the projects table

CHANGELOG

@@ -39,6 +39,7 @@ v 8.11.0 (unreleased)
   - Make branches sortable without push permission !5462 (winniehell)
   - Check for Ci::Build artifacts at database level on pipeline partial
   - Convert image diff background image to CSS (ClemMakesApps)
+  - Remove unnecessary index_projects_on_builds_enabled index from the projects table
   - Make "New issue" button in Issue page less obtrusive !5457 (winniehell)
   - Gitlab::Metrics.current_transaction needs to be public for RailsQueueDuration
   - Fix search for notes which belongs to deleted objects

db/migrate/20160802010328_remove_builds_enable_index_on_projects.rb

+class RemoveBuildsEnableIndexOnProjects < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def change
+    remove_index :projects, column: :builds_enabled if index_exists?(:projects, :builds_enabled)
+  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: 20160726093600) do
+ActiveRecord::Schema.define(version: 20160802010328) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -852,7 +852,6 @@ ActiveRecord::Schema.define(version: 20160726093600) do
   end
 
   add_index "projects", ["builds_enabled", "shared_runners_enabled"], name: "index_projects_on_builds_enabled_and_shared_runners_enabled", using: :btree
-  add_index "projects", ["builds_enabled"], name: "index_projects_on_builds_enabled", using: :btree
   add_index "projects", ["ci_id"], name: "index_projects_on_ci_id", using: :btree
   add_index "projects", ["created_at", "id"], name: "index_projects_on_created_at_and_id", using: :btree
   add_index "projects", ["creator_id"], name: "index_projects_on_creator_id", using: :btree