added Orchestration section

I see we are missing a section for "orchestration" -- way to do specific actions in defined order in distributed systems.

I've added couple of tools in the same pull-request.

Some other possible candidates are [Capistrano](http://capistranorb.com/) (with successors like [Mina](http://nadarei.co/mina/), [Func](https://fedorahosted.org/func/), [Rundeck](http://rundeck.org/).

Another section to introduce would probably be "Service discovery" (see [Consul](http://www.consul.io/), [Etcd](https://github.com/coreos/etcd) but I don't have a very clear vision of their usage so they probably should go to some other awesome list.