add: friendship model
add: status field in friendship model
add: test for listing user's friends
add: test for sending notification on friend request
add: notification model
Revert "add: notification model"

This reverts commit fa4d0110e4327e214bee5df955b21b81a23b7e09.
fix: friendship test
add: tests for notification
add: notification controller
fix: notification test
add: route for notification api
fix: friendship test
add: friendship index method
fix: flush redis when testing friendship
add: friendships routes
add: test for confirming friendship
add: controller methods for confirming friendship