fixed has many through
refactor extracted the has-many-through code to a seperate method
Merge pull request #59 from abenari/57_rebase

fixed has many through
Bump minor version number.
Raise an exception when negating an empty expression instead of generating wrong SQL
Merge pull request #64 from wvanbergen/fix_sql_issue

Raise an exception when negating an empty expression
Fix Gemfiles
RSpec deprecations
Bump version
fixed has_many_through join function for polymorphic relations