-  gitty_open(+Store, +Options) is det
 - Driver specific initialization. Handles setting up a Redis
connection when requested. This processes:
- redis(+DB)
 - Name of the redis DB to connect to. See redis_server/3.
 
- redis_ro(+DB)
 - Read-only redis DB.
 
- redis_prefix(+Prefix)
 - Prefix for all keys. This can be used to host multiple
SWISH servers on the same redis cluster. Default is 
swish.