adding debugger to gemfiles
rails32 :include of has_and_belongs_to_many associations -> default slave

This also contains a fairly large refactoring of how we pull off monkey
patching for slave-by-default stuff.
Merge remote-tracking branch 'origin/master' into ben/support_has_many_include_on_slave

Conflicts:
	gemfiles/rails32.gemfile
	lib/active_record_shards/default_slave_patches.rb
	test/connection_switching_test.rb
Merge pull request #8 from zendesk/ben/support_has_many_include_on_slave

Support has_and_belongs_to_many :include on slave by default