Runs migrations and adds seed data

csv_extract.rb updated so that it can be run from the rails console. There were some problems with getting it to work since the rails 4 upgrade. The schema is updated because migrations were run for a new dev db.
Initiates new balance handling

Start to adding new balance and bank balance calculation. Initial calculation is made on the rails server (excluding the current ledger month) and any current ledger calculations are made on the client.

New routes and new transaction class methods added with corresponding controller methods and backbone model.
Adds balance handling to ledger backbone view
Changes temporary ledger_month constant to Dec
Removes bk_download.csv from git