Improvements to gitlab example

[dustymabe]

The gitlab example uses redis and postgres but it doesn't use nested nulecules to achieve this. We should use the redis atomicapp and the postgres atomicapp within this application.

Additionally we should use images from the centos dockerfiles rather than the images under swordphilic on github.

@navidshaikh what do you think?

[navidshaikh]

The gitlab example uses redis and postgres but it doesn't use nested nulecules to achieve this. We should use the redis atomicapp and the postgres atomicapp within this application.

One, redis nulecule example has master and slave configured; this gitlab example does not use redis master and slave. Two, this example also shows how to write Nulecule Spec if you have multiple tiers in application (without using graphs).

Additionally we should use images from the centos dockerfiles rather than the images under swordphilic on github.

ACK! will test the example with centos dockerfiles images.