- Changed `IN` to `ON` in all note sentences in guides.

With rails/coffee-rails#61 (and #17241), the `.coffee` extension is
favoured over `.js.coffee`. Respectively, with rails/sass-rails#271
`.scss` and `.sass` are favoured over `.css.scss` and `.css.sass`.

Let's update the documentation to reflect that.

[ci skip]

References #18148.

Allow static asset serving from env variable (enhanced!)
Conflicts:
	railties/CHANGELOG.md

fixes #17893

[ci skip]

fixes this :

![http://i.imgur.com/86scI3a.png](http://i.imgur.com/86scI3a.png))

Even if this is not exactly the same, let's add a new-line character
instead of two spaces. While it's specified in the Markdown specs that
adding spaces at the end of the line creates a break-line tag, this is
a brittle approach as people may remove them saving the file on certain
editors.

[ci skip]

not 2 caveats with one of them being 2 config changes [ci skip]

to match arguments used in sprockets-rails [ci skip]

Follow up to #15636.

/cc @hundredwatt

Directives need to be placed on their own lines in order to work. Tested on: `Server version: Apache/2.2.22 (Ubuntu); Server built:   Mar 19 2014 21:11:15`

in Asset Pipeline guide.

[skip ci]

[ci skip]

Updated CHANGELOG.md with entry about :host in asset_url

The name of the gem is `uglifier` and all other references
use `uglifier`, not `uglify`.

[ci skip]

sprockets-rails 2.1 needs the precompile list to be available in all
environments.