[tor-relays] obfs4 - git how to ?

Trying to use obfs4 from git on a test bridge :

With "root" user: cd /home/TEST git clone https://git.torproject.org/pluggable-transports/obfs4.git ln -s /home/TEST/obfs4/obfs4proxy /usr/bin/obfs4proxy

torrc file : [...] ServerTransportPlugin obfs4 exec /usr/bin/obfs4proxy managed ServerTransportListenAddr obfs4 0.0.0.0:48001

In the log when starting Tor : [...] [warn] Could not launch managed proxy executable at '/usr/bin/obfs4proxy' ('Permission denied'). [...] Tor is still working and is connected to the network...

Humm, I think I've not understand how to use this source, and how to manage it ?!

Thx for you help :)