Add notes when booking an appointment

Ability to add notes when booking a lesson or for us to go in and add notes from the back end. We can see exactly what the lesson was for. For example. if we are using it to practice a solo and the child has 2 solos we like to say which one rehearsed. Or if one parent books a slot to rehearse a duo, we like to write a note that says the duo rehearsed and that it wasn't just a solo practice for the one who actually booked.