add a way to invalidate cache on multiple running rhodecode instances

Issue #347 resolved
Marcin Kuzminski
repo owner created an issue

When RhodeCode is used in multi-machine / multi instance setups, the cache invalidation mechanism should invalidate cache on each instance independently. Currently it invalidates one that hits the invalidate marker first.

I think it's easy enough to add <instance> prefix to cache table, and then each instance should check by prefix+repo_name.