What does our database look like?

Added database schema and some explanation of why the relationships are what they are
What are the waveforms?

Waveforms how a tone 'sounds.' Each of these take a particular note and makes it sound like it was coming out of a different electronic instrument.
Merge branch 'TLR-database-schema-diagram' of https://github.com/cnocon/Keyboard_App_2 into TLR-database-schema-diagram

Conflicts:
	README.md