diff --git a/app/models/category_group.rb b/app/models/category_group.rb
index a0cbb3f31e8..a4f5b51ef9d 100644
--- a/app/models/category_group.rb
+++ b/app/models/category_group.rb
@@ -23,3 +23,7 @@ end
 #  updated_at      :datetime         not null
 #  permission_type :integer          default(1)
 #
+# Indexes
+#
+#  index_category_groups_on_group_id  (group_id)
+#
diff --git a/db/migrate/20191022161944_add_index_on_group_to_category_groups.rb b/db/migrate/20191022161944_add_index_on_group_to_category_groups.rb
new file mode 100644
index 00000000000..ba3578ca9bf
--- /dev/null
+++ b/db/migrate/20191022161944_add_index_on_group_to_category_groups.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddIndexOnGroupToCategoryGroups < ActiveRecord::Migration[6.0]
+  def change
+    add_index :category_groups, :group_id
+  end
+end