I noticed today that my brake resivour was leaking where it connects to the master cylinder not very familiar with it what would cause this?

 

U sure its leaking or its just residual fluid?

I would inspect the whole thing and find where its leaking from. Might be a cracked reservoir.

 

Spray it down clean with brake parts cleaner, rinse gently (watch out for the electrical components like the ABS relay and such) or wipe it all off with a rag and see if it comes back.

Also fill the brake reservoir and see if it drops over a month. It's not accurate to check it right now because that fluid level does decrease as the brake pads wear and the brake caliper pistons are further extended as those pads wear.

EDIT: If that fluid does start to pool around the rear of the MC again then it's probably a failing seal in the brake master cylinder.