Fix permissions

The text just sets the ownership and ignores that defaults on unix
are to have newly created dirs be readable by everyone.
This closes the database to unauthorized users on multi-user systems.

DEPLOY.md

@@ -150,6 +150,7 @@ If you use the default database path you also need to run this:
 ```bash
 sudo mkdir -p /var/lib/matrix-conduit/
 sudo chown -R conduit:nogroup /var/lib/matrix-conduit/
+sudo chmod 700 /var/lib/matrix-conduit/
 ```
 
 ## Setting up the Reverse Proxy