CIMI: Replaced DataMapper with Sequel ORM
CIMI: Migrated database models to use Sequel
CIMI: Updated CIMI models to use Sequel methods and helpers
Remove index creation errors when database is already created
CIMI: Moved database initialization to models.rb

This will allow proper testing of database
Fixed bugs in storing entity data to database
Added validation to database models
Initial database tests for CIMI frontend