Here are some useful database-related CLI commands in Rails. Here for my own reference since I seem to forget all the time!
Also handy is the source code for all these wonderful commands.
Revert all migrations.
Drops the database, recreates it and runs all migrations.
Truncate (empties) all tables in database.
Truncates database and loads seeds.
Rollback last migration.
Rollback last migration and then run it again.