add new readme
add gitignore
add udp-broadcast-relay as submodule
[!NOTE] This is an adaptation of @britannic's repo, the original README with how to configure the relay can be found here
# compile udp-broadcast-relay for ER-X
make DEVICE=ER-X
# upload ubnt-bcast-relay_ER-X.tgz to your device
tar -xvzf ubnt-bcast-relay_ER-X.tgz
sudo bash ./ubnt-bcast-relay/setup.sh