added model Tag, basic controller for it and seeding of all english tagset
done: ParadigmType model and seeding of some types
broke ParadigmsController#index: can not access paradigm.paradigm_type
deleted unused migration
invalid files removed
paradigm is now resolved to its paradigm_type.name
removed unnecessary migration
paradigms#create now correctly redirects to paradigms#new
Word model refactored to point to Tag through tag_id (belongs_to association)
seeding initial data into Word and Task
started with paradigms#edit
paradigms#edit almost working, except that it saved duplicates (see README #1 issue)
done with editing a single paradigm
when editing paradigms#new, the form is prepopulated with data from db if it exists
unassigned tasks added to seeding