You may want to set up /etc/host such that foo.bar resolves to localhost:5000.
sudo ifconfig lo0 10.0.0.1 alias
echo "rdr pass on lo0 inet proto tcp from any to 10.0.0.1 port 80 -> 127.0.0.1 port 5000" | sudo pfctl -ef -
Then, add this to /etc/hosts:
10.0.0.1 foo.bar