You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: user_subscriptions_controller.rb
    path of file: ./repos/forem/app/controllers
    
    the code of the file until where you have to start completion: class UserSubscriptionsController < ApplicationController
  before_action :authenticate_user!

  USER_SUBSCRIPTION_PARAMS = %i[source_type source_id subscriber_email].freeze

  def subscribed
    params.requi
    
  def create
    rate_limit!(:user_subscription_creation)

    user_subscription = UserSubscriptions::CreateFromControllerParams.call(current_user, user_subscription_params)

    if user_subscription.success
      rate_limiter.track_limit_by_action(:user_subscription_creation)
      render json: { message: "success", success: true }, status: :ok
    else
      render json: { error: user_subscription.error, success: false }, status: :unprocessable_entity
    end