added documentation - usecases & draft design views in readme.md
added documentation - usecases & draft design views in readme.md

Signed-off-by: Wonho Lim <86f7e437faa5a7fce15d1ddcb9eaeaea377667b8@wono.me>

sounautic/SoundBox,sounautic/SoundBox,sounautic/SoundBox