allow to disable completed submission emails

app/controllers/user_configs_controller.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class UserConfigsController < ApplicationController
+  before_action :load_user_config
+  authorize_resource :user_config
+
+  ALLOWED_KEYS = [
+    UserConfig::RECEIVE_COMPLETED_EMAIL
+  ].freeze
+
+  def create
+    @user_config.update!(user_config_params)
+
+    head :ok
+  end
+
+  private
+
+  def load_user_config
+    return head :not_found unless ALLOWED_KEYS.include?(user_config_params[:key])
+
+    @user_config =
+      UserConfig.find_or_initialize_by(user: current_user, key: user_config_params[:key])
+  end
+
+  def user_config_params
+    params.required(:user_config).permit!.tap do |attrs|
+      attrs[:value] = attrs[:value] == '1' if attrs[:value].in?(%w[1 0])
+    end
+  end
+end