Soft Delete callback

[skrishnegowda]

No description provided.

[kelaraj]

Nice implementation. My understanding is these changes will be completely backwards compatible because they are only invoked if a consumer of this gem specifies before_soft_destroy or after_soft_destroy. Is my understanding correct?

We'll obviously need to run our Delphius test suite (I assume that's our only internal consumer of this gem) with this new version just to confirm that there are no issues.

It'd also be great to add some tests to test_core.rb.

@christopherchiu you mentioned that you're pretty familiar with this gem. Any concerns?

[christopherchiu]

This looks good. Awesome job remembering to update the README file. Like @dpmehta02 said, we should add a test to make sure the callback is getting called.