Enhancing feed_manager to follow a few models

[a-ta-ta]

Using Stream-rails, I noticed that feed_manager allows users follow just other users.

However, nowadays people follow communities not less than users and it would be awesome to make the current feed_manager more flexible to use custom models for dealing with feeds.

[joshmenden]

I agree with this. I would also like to be able to override the feed that an activity is posted to. It looks like in the source code it is hardcoded to a "user" feed, but what if I want the activity to be posted to a "band" or "artist" feed?

[joshmenden]

The above problem of a hard coded "user" is addressed in: https://github.com/GetStream/stream-rails/pull/94