set up PreferenceList models and tests
add preference_list model migrations, tests and model methods for checking against preference lists to create notifications for renters
ignore DS_STORE
Merge branch 'master' of https://github.com/jalant/office_classifieds
create notification-on-save after-filter on OfficeListing model
Merge branch 'master' of https://github.com/jalant/office_classifieds