Seninel support

[MyDigitalLife]

As of version 1.1.0 Predis supports Sentinel https://github.com/nrk/predis/releases/tag/v1.1.0. However there isn't a way to use Sentinel using the SncRedisBundle as far as a can find.

I have found 2 pull requests that attempted to add code needed for it to work. However up until now they have both not been merged and don't look to be active.
#274
#307

Is there a plan on when this support will be added or will i need to create my own fork and implement is to get this any time soon?

[MyDigitalLife]

I checked out the code created by @othillo in #307 and it works. The only thing i did was add the possibility to select a database. If that pull request is merged this issue can be closed.