Added extra index for faster enumeration of CI builds

db/migrate/20151020173906_add_ci_builds_index_for_status.rb

+class AddCiBuildsIndexForStatus < ActiveRecord::Migration
+  def change
+    add_index :ci_builds, [:commit_id, :status, :type]
+  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: 20151019111703) do
+ActiveRecord::Schema.define(version: 20151020173906) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -110,6 +110,7 @@ ActiveRecord::Schema.define(version: 20151019111703) do
   end
 
   add_index "ci_builds", ["commit_id", "stage_idx", "created_at"], name: "index_ci_builds_on_commit_id_and_stage_idx_and_created_at", using: :btree
+  add_index "ci_builds", ["commit_id", "status", "type"], name: "index_ci_builds_on_commit_id_and_status_and_type", using: :btree
   add_index "ci_builds", ["commit_id", "type", "name", "ref"], name: "index_ci_builds_on_commit_id_and_type_and_name_and_ref", using: :btree
   add_index "ci_builds", ["commit_id", "type", "ref"], name: "index_ci_builds_on_commit_id_and_type_and_ref", using: :btree
   add_index "ci_builds", ["commit_id"], name: "index_ci_builds_on_commit_id", using: :btree