models-relation: Specify User relations
models-relations: Add posts count to users with auto-increment/decrement
models-relations: Add likes count to users with auto-increment/decrement
models-relations: Add comments count to users with auto-increment/decrement
models-relations: make sure comments and likes are destroyed when post is destroyed
models-relations: make sure to destroy timeline if Comment, Like, Post or Relationship are destroyed
models-relations: Add following_count to User model
models-relations: Add followers_count to User model