Feature suggestion: Allow a block to passed, following same standard used in Ruby & Rails

[salgadobreno]

Hi, thanks for the cool gem 8)

So, there's a feature suggestion, it would be nice to allow passing a block to be yielded when there's a conflict not in Hash or Array lets say, as Rails deep_merge and Hash merge do. It could serve for things like doing calculations and such or allowing the decision to override a value to be done in other ways, in my use case, I wanted to sum one of the values.

I'll probably try coming up with a monkey patch for my purposes, I'll say already I'm very lazy but I could try coming up with a pull request, specially if the feature is desirable.

[science]

Hey @salgadobreno - seems like a great idea (I'm the original author, but not the current maintainer). I believe I wrote this before that practice was standardized, so it would be great to bring this lib inline.

I think you'd approach this by providing block handling on this line:
https://github.com/danielsdeleo/deep_merge/blob/master/lib/deep_merge/core.rb#L78

And then on these wrapping methods: https://github.com/danielsdeleo/deep_merge/blob/master/lib/deep_merge/deep_merge_hash.rb

Then you'd need to track state of the merge with some new variable starting at that L78 above. Shouldn't be too tough, but deciding what is a conflict and what isn't will be a bit of a judgment call maybe, but I'd definitely encourage you to give it a try, and send a pull request here.. I think I have perms to approve PRs on Daniel's repo, so you can tag me or him to review.