Fill in README

[kaspth]

This adds a bunch of information on our conventions and how to set up dev data plus reuse it in tests.

[kaspth]

@tcannonfodder does this get to some of what you were saying in #58?

[tcannonfodder]

@tcannonfodder does this get to some of what you were saying in #58?

Not quite; I was thinking about how Rails’ generators operate. In short, similar to factorybot or fixtures, if I generate a new model using rails generate model, I would like Oaken to stub out a new file, rather than having Rails generate a fixture I’ll never use

[kaspth]

@tcannonfodder ah got it. Yeah, that's interesting. I'm not quite sure where we'd add that data since we don't have a 1-1 mapping of a model to a file. But we could definitely make it so that fixture files aren't generated when you're using Oaken.

[tcannonfodder]

That would work! I just wanna make sure my generators are working as expected & don’t make cruft 😄