Please add filters/extensibility to allow Redis AUTH and SELECT commands

[l3rady]

Hi,

Please can we get some means to auth and select DB with this plugin when using redis srcache?

A simple filter to allow some pre commands would suffice to pass the commands:

AUTH [username] [password]
SELECT [db_number]

This would allow those that don't have an open redis db connection or those not using the default db0 connect and purge the cache.

You already provide a way to set the HOST, PORT and PREFIX via some defines but its not quite perfect.

Thank you