Ability to specify attributes for approval

[gerb-ster]

I think it would be useful if one could specify which attributes of a model should be approved and which should be updated without approval. Sometimes you only want to approve a specific attribute.

[cjmellor]

It's a good idea. I'm open to PR's for it, but might look into it myself down the road also

[gerb-ster]

I've opened a PR for this:

#46

[cjmellor]

Cool, I'll keep an eye on it.