Access Control Documentation: Explain special and magic refs

Gerrit makes use of several special and magic references outside of
the refs/heads and refs/tags namespaces. This is now explained in
detail.

Change-Id: I22c47f2336d16fe23bea46035583a9a1e38eb2d4
Signed-off-by: Fredrik Luthander <fredrik.luthander@sonymobile.com>
1 file changed