Feature/session db connection

Hello Laravel Team!

In reaction to this feature request (https://github.com/laravel/laravel/issues/884) I made the edition to support it.

More explanation about this feature - edition is not needed I hope.

If you don't like the edition, or I made a mistake somewhere (nearly impossible since I tested the code I wrote) please bug me about it :)

Btw. This is my very first contribution to an open-source project, plus this is the first framework what I truly love!