Prevent error when calling <association>_ids=

Error raised when creating a delete statement as a result of calling
association's *_ids= method.

Error: undefined method `abstract_class?' for Object:Class
Merge pull request #108 from envylabs/master

Prevent error when calling <association>_ids=
add support for recursive CTEs
Merge pull request #107 from ccutrer/recursive-cte

add support for recursive CTEs
Removes unnecessary columns from migration
Removing dead test code
Relation.with accepts Arel::SelectManager
Uses existing visitor instead of creating a new one
Version bump

[ci skip]
Created failing spec for inferred table name
Fixes where issue with hashed wheres and array values

Closes #111
Merge pull request #112 from dockyard/111_relation_table_name

Fix for issue 111
Add homepage to gemspec
Merge pull request #113 from tmaier/patch-1

Add homepage to gemspec
Remove .rspec

MiniTest rules!
Prepare for Rails 4:
loosen AR version dependencies;
implement gemfiles testing pattern;
improve readme;
add rake task for running tests against all supported AR versions;
update travis.yml;
require library being tested last in test_helper;
Update querying.md

fixes grammatical error
Merge pull request #127 from rall/patch-1

Update querying.md
Merge pull request #119 from dockyard/remove-rspec

Remove .rspec
Merge pull request #126 from trumaker/prepare_for_rails4

Prepare for Rails 4: