Heroku timeout when sending emails

I am on Heroku with a custom domain, and I have the Redis add-on. I need help understanding how to create a background worker for email notifications. Users can inbox message each other, and I would like to send a email notification to the user for each new message received. I have the notifications working in development, but I am not good with creating background jobs which is required for Heroku, otherwise the server would timeout.

Messages Controller:

  def create    @recipient = User.find(params[:user])    current_user.send_message(@recipient, params[:body], params[:subject])    flash[:notice] = "Message has been sent!"    if request.xhr?        render :json => {:notice => flash[:notice]}    else        redirect_to :conversations    end  end

User model:

def mailboxer_email(object)    if self.no_email      email    else        nil    endend

Mailboxer.rb:

Mailboxer.setup do |config|  #Configures if you applications uses or no the email sending for Notifications and Messages  config.uses_emails = false  #Configures the default from for the email sent for Messages and Notifications of Mailboxer  config.default_from = "no-reply@domain.com"  #Configures the methods needed by mailboxer  config.email_method = :mailboxer_email  config.name_method = :name  #Configures if you use or not a search engine and which one are you using  #Supported enignes: [:solr,:sphinx]  config.search_enabled = false  config.search_engine = :sphinxend