Move buildURL and related methods to a mixin

[amiel]

This is my first step towards emberjs/rfcs#4.

The intent here is to separate url building from the RESTAdapter so that
it can eventually be included in other adapters and hold the logic for the
path template concept described in emberjs/rfcs#4.

Even though it's a fairly small change, I've written this pull request to:

1. Get my foot in the door. Since this is my first pull request to ember-data, I figure starting small is a good idea.
2. Make a place for the url-templates feature before starting a longer-lived branch. I think this will help prevent conflict management overhead as I work on the url-templates feature.

[fivetanley]

This seems great to me! I wonder how this will affect the website. I think we still want the methods to show up on the documentation for DS.Model.

Do you have ruby installed? If so can you try building this in the website repo and post some screenshots of the doc output?

[amiel]

I do have Ruby installed, but have never generated the API docs before. I'll try following the instructions at https://github.com/emberjs/website/blob/master/README.md and post the results.

[bmac]

Should we be exporting the BuildUrlMixin on the DS global?

[bmac]

@amiel I suspect @fivetanley is correct and the buildURL and urlPrefix will not show up on the RESTAdapter class in the docs. I you will likely need to define a BuildUrlMixin for your new mixin and use the YUIDoc @uses syntax to show that the RESTAdapter mixes in the BuildUrlMixin's methods.

[amiel]

Hmmm, I can't get the docs to generate:

$ pwd
/Users/amiel/src/github/ember/website
$ bundle exec rake generate_docs
Generating docs data from /Users/amiel/src/github/ember/ember.js... Could not locate Gemfile or .bundle/ directory
You are missing dependencies for /Users/amiel/src/github/ember/ember.js. Attempting to install now.
bundle install
Could not locate Gemfile or .bundle/ directory
rake aborted!

Should there be a Gemfile in the ember.js repo?

I'm using ruby 2.1.0.

[amiel]

@bmac @fivetanley I've tried for a while to generate the API docs to verify. Since I couldn't get anything working, I've just made the changes you suggested.

I wasn't going to export BuildURLMixin on the DS global initially, but if it helps the docs, I'm all for it.

[bmac]

This will need a doc block at the top with an @class BuildURLMixin annotation for the methods below to get correctly attributed to the correct class.

[amiel]

@bmac ok, I've added this, and some documentation for how to use BuildURLMixin. It is not very thorough, but my goal is to completely change the way url building is done (with url templates), and I don't want to spend too much time improving documentation for something that will soon be obsolete.

[amiel]

Ok, I've got the docs building now, thanks @rwjblue.

Here's what it looks like now: