Simulate systemd

Since WSL2 has no systemd, we can simulate service using nohup by add the followings to ~/.bashrc

# run trojan at shell launch if no trojan is running.                      
if ! pgrep "trojan" > /dev/null; then
    nohup bash ~/trojan/run.sh </dev/null >~/trojan/nohup.out 2>&1 &
fi