error exception

def create
    begin
      @merchant = Merchant.find_by!(:username => params[:username])
      if @merchant
        render json: {error: 'duplicate', message: "Username anda sudah terdaftar"}, status: :unprocessable_entity
      end
    rescue Mongoid::Errors::DocumentNotFound
      @merchant = Merchant.new()
      @merchant.name = params[:name]
      @merchant.username = params[:username]
      @merchant.password = params[:password]
      @merchant.password_confirmation = params[:password_confirmation]
      @merchant.phone_number = params[:phone_number]
      @merchant.max_waiting_time = params[:max_waiting_time]
      @merchant.open_hour = Time.parse(params[:open_hour])
      @merchant.close_hour = Time.parse(params[:close_hour])
      @merchant.address = params[:address]
      @merchant.location = {:lng => params[:lng].to_f, :lat => params[:lat].to_f}
      @merchant.banner_image = params[:banner_image]
      @merchant.profile_image = params[:profile_image]
      @merchant.menu_type = params[:menu_type].to_a
      @merchant.user = @user
      puts @merchant.location
      if @merchant.save
        render json: @merchant
      else
        render json: {errors: @merchant.errors.full_messages},
               status: :unprocessable_entity
      end
    end
  end