NOT NULL fields and validations.

[brunoocasali]

Hello!

Following our guides, we don't need to use t.string :name, null: false for example in our migrations, but is good to database when rails fails (if it fails). What did you think about it? Is a good tip add this and refactor our code?

Thx!

[felipefontoura]

@brunoocasali it's a good idea to add t.string :name, null: false to our migrations.