Can't be used with latest meta_search under Rails 3.1.

[budu]

This is really unfortunate, two of my favorite gems!

Bundler could not find compatible versions for gem "arel":
  In Gemfile:
    meta_where (~> 1.0.4) depends on
      arel (~> 2.0.7)

    meta_search (~> 1.1.0.pre2) depends on
      arel (2.1.4)

[ernie]

Please see https://github.com/ernie/meta_where#readme and http://metautonomo.us/2011/08/31/rails-3-1-and-the-future-of-metawhere-and-metasearch/