Started branch for ch 10
Listing 10.1 The Micropost migration.
Listing 10.2 The initial Micropost spec.
Listing 10.3 Tests for the validity of a new micropost
Listing 10.4 A validation for the micropost's user_id
Listing 10.5 A test to ensure that the user_id isn't accessible.
Listing 10.7 Making the content attribute (and only the content attribute) accessible.
Listing 10.8 Tests for the micropost's user association
Listing 10.9 A test for the user's microposts attribute.
Listing 10.10 A micropost belongs_to a user.
Listing 10.11 A user has_many microposts
Listing 10.12 The complete factory file, including a new factory for microposts
Listing 10.13 Testing the order of a user's microposts
Listing 10.14 Ordering the microposts with default_scope
Listing 10.15 Testing that microposts are destroyed when users are.
Listing 10.16 Ensuring that a user's microposts are destroyed along with the user.:
Listing 10.17 Tests for the Micropost model validations
Listing 10.18 The Micropost model validations
Listing 10.19 A test for showing microposts on the user show page
Listing 10.20 Adding microposts to the user show page