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: proposals_controller.rb
    path of file: ./repos/osem/app/controllers
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

class ProposalsController < ApplicationController
  before_action :authenticate_user!, except: [:show, :new,
    
  def registrations; end

  private

  def event_params
    params.require(:event).permit(:event_type_id, :track_id, :difficulty_level_id,
                                  :title, :subtitle, :abstract, :description,
                                  :require_registration, :max_attendees, :language,
                                  speaker_ids: []
                                 )
  end

  def user_params
    params.require(:user).permit(:email, :password, :password_confirmation, :username)
  end
end