Add getting started index and experienced developers guide (#12)

[ryan0x44]

Initial version of a Getting Started Guide for Experienced Developers.

Ideas for improvements:

• More code examples
• Add "Configuration: How should Go kit services be configured?"
• Add "Caching: How should Go kit services interface with cache systems?"

I hope this gives us a good place to start.

[peterbourgon]

"A Service typically glues multiple Endpoints together."

[ryan0x44]

Are you saying that you might have 4 Endpoints (e.g. create, edit, update, delete ToDo items) and you might have a Service that glues them together (e.g. the ToDo service)?

[peterbourgon]

Yes. (Did you really write this just now, in October, or was it GitHub's replication lag?)

[peterbourgon]

A bit about the two type of middlewares (Service and Endpoint) would be useful, and then it would follow to mention how to layer in behavior at the Transport level with Before, After, and Finalizer funcs.

[peterbourgon]

Ah, okay, I see. When we were talking, I envisioned something different for these guides: basically, the stringsvc tutorial, except much more fleshed-out, changed to end with a REST-y transport like profilesvc, and narrated in different ways (and perhaps with different levels of detail) depending on the target persona.

But If this is what you had in mind all along, then that's great; I'd just say each of these items belong in an expanded FAQ, and we should drop the guides. As it stands now my sense is that it's too short, and too conceptually similar to the FAQ, to warrant being a separate set of things.

WDYT?

[peterbourgon]

I've moved all of this stuff into the FAQ, and re-org'd it a bit. Does it look OK? With a LGTM I'll close this PR and get to work on #14.

[ryan0x44]

FAQ is looking good! I would really love to see the Persistence section added to the FAQ (maybe under More specific topics), and I think the examples from the Dependency Injection section could be worked into the related FAQ section as well.