Add `decorates_assigned` to README

[ci skip]
80-char wrap

[ci skip]
Avoid minitest-rails deprecation warning
Merge pull request #511 from haines/decorates_assigned_readme

Add `decorates_assigned` to README
Document how to stub route helper functions in isolated tests. Addresses #506.
Fix `CollectionDecorator#find`

Deprecates the use of ActiveRecord's `find` method on a collection
decorator.

Closes #509
Merge pull request #514 from haines/find_method

Fix `CollectionDecorator#find`
Improve documentation about stubbing route helpers

* Get rid of an unnecessary newline
* Change 'include Rails' to 'require Rails'
* Clarify when you would need to explicitly include ViewHelpers
* Switch from mocha `stubs` to RSpec `stub`
Merge pull request #513 from carols10cents/route_stubbing_documentation

Document how to stub route helper functions in isolated tests. Addresses...
Return self from CollectionDecorator#replace

Closes #516
Remove outdated documentation

Closes #522
Merge pull request #524 from haines/replace

Return self from CollectionDecorator#replace
Fix generators path

Closes #526
Fix decoration of unsaved collection associations

Calling `#decorate` on an unsaved collection association forced a
db lookup, clearing any items that have been added (e.g. using
`#build`).

Closes #518.
Merge pull request #530 from haines/decorating_unsaved_associations

Fix decoration of unsaved collection associations
delegate blank to source
Merge pull request #532 from buddhamagnet/master

Delegate `blank?` to source
Add spec for #blank? delegation
Fix build failure

rspec-rails 2.13.1 checks Rails.version when loading RailsExampleGroup
which is used by ammeter. Therefore we need to require rails.
use block_given in module_namespacing