part1-knex migrations and seeds

[elliehoward]

Needs a better explanation for common errors such as if you dropped a table that you want to migrate, yet the migration is still in the knex_migration table. So that when you try to run knex:migrate latest you get a message saying the table is already up to date and the migration never occurs. Also I spent awhile not knowing to make sure I was working in the test environment rather than development when running the migrations and rollbacks.