Sync#reserve simply returns a NullController to not do anything
modify test for Sync#reserve
bump version to 2.0.2
Remove support for Ruby 1.8.7

Ruby 1.8.7 is now officially deprecated, so it's not worth the effort to
offer ongoing support.
add redefine_constant spec helper to eliminate warning
rename spec User method to distinguish from the attribute name
Update test suite's ActiveRecord dependency from 2.3 to 4.0
add beanstalk install to .travis.yml
change == back to eql in test

Hopefully this will get Travis CI to pass