Allow to require engine gem just after requiring rails modules

[pabloh]

This fixes issues like https://github.com/pat/combustion/issues/27. Without having to do to any work around.

[pabloh]

This would also allow only do require 'bundler/setup' at spec_helper.rb instead of doing

require 'bundler'

Bundler.require :default, :test

Maybe I could add a commit to update the README file if you want.

[pabloh]

@pat, @parndt: no comment about this so far?

I think could settle for at least some mean to execute code after the rails modules are loaded but before Combustion::Application.initialize! is run. Like having some Combustion attribute where you could pass a block to be run, or maybe passing a block to Combustion.initialize! directly.

[pat]

@pabloh I'd be open to the idea of passing a block to Combustion.initialize that gets called just prior to Combustion::Application.initialize!. That feels a bit cleaner than this approach of guessing the gem name and loading it.

[pabloh]

@pat I changed commits I originally sent. Do you think the current changes are acceptable?, I'm basically calling 'Bundler.require' after requiring the rails modules and just before calling Application.initialize!. I also updated the README since the source of the problem I was having was when calling 'Bundler.require :default, :test' at the spec_helper.rb file.

The other approach of yielding a block just before calling Application.initialize!, will also work but I think this one is simpler.

[pabloh]

@pat @parndt , any feedback on this?

[parndt]

One (potential?) snag is that this binds us to Bundler inside of Combustion's source code whereas we previously weren't.

[pabloh]

@parndt, since when using rails you're already heavily binded to bundler, I don't understand how that could be a problem.

[pat]

I've merged this in - I agree that we're pretty closely tied to Bundler anyway, as that's what Rails uses and this gem's all about testing Rails-related libraries.