title: Sending Project Invites in Rails
body: <p>Hey all, I'm looking for a way to add an invitation strategy to my Rails app. I'm using Devise for authentication, and like the look of <a href="https://github.com/rymai/devise_invitable" rel="noreferrer">devise_invitable</a>, but as far as I can tell, that gem only allows you to invite new users to the system.</p>
  
  <p>In my app, a user has the ability to invite other users (using email) to join his current project. If that email address exists, the user is added; if the address doesn't exist, I'd like to send a project-specific invitation to that email address. If the user already has an account, she can log in and bind her account to that project. If not, she can create a new account.</p>
  
  <p>Does anyone have any advice on where to look for such a system?</p>