Remove index of `created_at` on themes

db/migrate/20231107200845_optimise_indices.rb

@@ -6,5 +6,7 @@ class OptimiseIndices < ActiveRecord::Migration[7.0]
     remove_index :users, :screen_name, unique: true
     add_index :user_bans, :expires_at, order: :desc
     add_index :announcements, %i[starts_at ends_at], order: :desc
+    remove_index :themes, %i[user_id created_at]
+    add_index :themes, :user_id
   end
 end

db/schema.rb

@@ -291,7 +291,7 @@ ActiveRecord::Schema[7.0].define(version: 2023_11_07_200845) do
     t.integer "input_placeholder", default: 7107965, null: false
     t.integer "raised_text", default: 0, null: false
     t.integer "raised_accent_text", default: 0, null: false
-    t.index ["user_id", "created_at"], name: "index_themes_on_user_id_and_created_at"
+    t.index ["user_id"], name: "index_themes_on_user_id"
   end
 
   create_table "totp_recovery_codes", force: :cascade do |t|