Add a gitter chatroom

[rishavs]

Just stumbled onto this library. It is extremely interesting and fresh but its a shame that there doesn't seems to be a community around it. Adding a simple Gitter chatroom will a step in this direction.

[drewjbartlett]

@rishavs what is this? Could you help us set this up?

[rishavs]

@drewjbartlett
Any repository owner can set up a slack-like chat at https://gitter.im

Shouldn't take more than a few clicks. And you get full github integration along with a place for the community to hang around.