Add further indices to submissions table

These two indices are expected to improve the performance, especially for submission statistics.

Author: MrSerth

db/migrate/20241105212201_add_indices_to_submission.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class AddIndicesToSubmission < ActiveRecord::Migration[7.2]
+  def change
+    add_index :submissions, :updated_at, order: {updated_at: :desc}
+    add_index :submissions, :cause, using: :gin, opclass: :gin_trgm_ops
+  end
+end