Link fix in documentation
Merge pull request #65 from trevor/patch-1

Link fix in documentation
Changed to Mongoid 3.0 syntax. All specs passing but one.

Notes:
  - Replaced find(..) with find_by_slug(..) when finding
    by slug.
  - Spec asserting that a find on id can not happen is
    not passing since I am not sure why this shoudl be
    the case.
Refactor: store all slugs in a single field of Array type.

Notes:
 - removed optional index. Mongoid is indexes the id by default
   and a slug is just an alternative id.
 - slug.last is the latest slug.
removed the :as feature and renamed slug field to _slugs
reserved words should default to :new and :edit
code cleanup: moved by_slug to module included section
Minor plumbing
Remove by_slug

Scope feels of limited general utility
Remove find_by_slug and ilk
Insignificant plumbing
Don't index scoped slugs
Merge branch 'slug-array'
Copy Mongoid travis conf
Remove ruby-head
Fixed broken #find.

Mongoid::Slug::Criterion was not being included into Mongoid::Criteria correctly, and as a result no slug aware #find method was implemented. There were no specs testing this.

This commit removes that module/include pattern and replaces it with direct extension of the Mongoid::Criteria class. The #find method will now attempt to determine whether it is being supplied with _ids or slugs and responds accordingly.
added items to CHANGELOG
added back index on scoped items
Use more appropriate method to test if arguments supplied to #find are BSON::ObjectId strings.
optimization: introduce limit on finding by slugs