Cache Bundler to S3 on Travis
Workaround for CSV#generate encoding issue.
Add integration tests
maybe the latest Bundler isn't needed anymore?
Cache the test app to S3 on Travis
turns out tar remembers the folder structure!
create proper URLs
actually save files when `:as` isn't provided
update `rake setup` to not run if test app exists
Add encode options
add no-default-user option to active_admin:devise generator

When using active admin with a customized User model living in the
main app, it is common to add further validations for profile
attributes etc. Creating a user in the generated migration may fail
then since not all required attributes are present.

In those cases it's better to setup the initial user via a database
seed. This option allows other engines, which bundle active admin, to
invoke default active admin generators while still providing their
default user via a seed.
Docs: custom authentication now more obvious

I was having a bit of difficulty figuring out where exactly to implement my own authentication method, until I found http://dan.doezema.com/2012/02/how-to-implement-a-single-user-model-with-rails-activeadmin-and-devise/ and realized I should be implementing them in ApplicationController.

Hoping this helps fellow ActiveAdmin newbies.
update authorization adapter docs to use GFM
indentation fix
Refactor dependency checking to use requirement strings
Make devise soft dependency

Load devise only when the dependency is fulfilled. Show an error
message when running generator without devise gem.

Fixes #542.
Add runtime check for Devise version
change locale key order for better comparing to en version
add missing locale key de.active_admin.comments.author_missing
add missing locale key de.active_admin.access_denied