added tag model, exercise_taggings and meditation_taggings models, added three tag methods to exercise and meditation models, created tags_controller and tags view/index, as well as related migration files for tag and taggings tables.
fixed some stuff, still trying to fix the labels on the tag index page - not sure why they are acting so funny
fixed labels in tag index
successfully set up doctrines tagging, and added Assent and Ethics as examples in the view. Also created Doctrine New action to put in the file names (note, input them without / before and without html.haml.
Merge pull request #16 from Henryvw/tags

Tagging of exercises, meditations and doctrines. Doctrines tagging is via a new doctrines model and New action in the controller to input file names which are then converted into URLs.