Hit count

[timadevelop]

Create hit counting for services and posts.

use redis / rabbitmq for hit counting

[timadevelop]

I'll implement this later because we need at least a small MVP for a beta.

[timadevelop]

The simplest strategy is to save hit counts in Redis and every 2/5/8 hours to update DB instance.
So in service model we need to have a @property hit_count which returns something like:

instance.hit_count + redis.get('HIT_COUNT_SERVICE_{}'.format(instance.id))