Allow to choose between Procfile.dev or Puma plugin

[javierav]

after the PR #300 has been merged, the user should be allowed to choose whether to use the Procfile.dev or the Puma plugin in the installation generator. Currently the Procfile.dev and the foremangem installation are always used.

[flavorjones]

@javierav This is a great idea! If you'd like to attempt to implement it, I'd gladly review a PR.

[javierav]

Hi Mike!

I started thinking about it, but I don't see what is the best way to parameterize the generator. Any suggestions?

[javierav]

#331

[flavorjones]

I think, long-term, the real solution here is to use the engine server hook approach from #347. I'll be working on landing some version of that patch.