Add code examples and documentation for every engine

[indexzero]

(Purposeful duplicate of #107)

There should be working code examples and documentation for using every single engine resourceful has to offer.

Code examples go here: https://github.com/flatiron/resourceful/tree/master/examples/enginename

Documentation goes: https://github.com/flatiron/resourceful/wiki/Engines-Usage

sub-ticket of #91

[brucou]

Do you have any examples as per how to use with socket.io? I see it mentioned in the documentation as an available engine but I can't see how to use it.