NewInviteController creates a new instance of an InviteController and returns a pointer to it.

NewUserController creates a new instance of a UserController and returns a pointer to it.

NewViewController creates a new instance of a ViewController and returns a pointer to it.

InviteController is responsible for handling requests for Invite HTTP APIs.

UserController is responsible for handling requests for Account HTTP APIs.

ViewController is responsible for serving HTML views to the end user via HTTP.