Tests for the validity of a new micropost
Added validation for the micropost's user_id
Tests for the micropost's user association
Added test for the user's microposts attribute
Implement association between user and microposts
Fix typo in testing
add new factory for microposts
Testing the order of a user's microposts
Add default scope to order micropost
Testing that microposts are destroyed when suers are
add option to has_many to ensure a user's microposts are destroyed along with the user
Add tests for the Micropost model validations
Add Micropost model validations for content being a maximum of 140 characters