Update README
Update README

This commit updates the instruction that a 'project' must exist
previously and it adds the 'metadata' name in the files type supported.

Signed-off-by: Luis Araujo <b6d7d6f4aa54f668b4b655090642bd1a1429cbcb@collabora.co.uk>

terceiro/squad,terceiro/squad,terceiro/squad,terceiro/squad