Assignment 4: Import helper macros
Assignment 4: Exclude some tags from the list
Link to "The Clean Architecture" description
Assignment 4: Reinforce different between Flickr and Entity tag
Assignment 4: Make sure the default initialisers cannot be called
Assignment 4: Prepare model for showing list of images per tag
Assignment 4: Display list of images per tag
Assignment 4: Fix dropped cache of photos with a shared instance