Add rake initializer

[naoty]

This task prints out initializers for an application. It is useful to
develop a rubygem which involves the initialization process.

[chancancode]

Should this be rake initializers? ( <--> rake routes)

[rafaelfranca]

We have rake middleware 😢

[chancancode]

Hmm true. But in that case it's going to disagree with either one of them anyway, so might as well go with whatever we think is "better" 😛

There's also rake annotations, so my vote is for plural!

[rafaelfranca]

👍

[chancancode]

Committed 9e80c29 😃

[andrewhr]

rake middleware could be read like "Give me our middleware stack". I like to imagine that's why it's in the singular 🚲 🎨

[naoty]

I'm also agree with rake initializers. 👌