A possibility to enable run at bootup is to use the systemd files. systemd provides a standard process for controlling what programs run when a Linux system boots up. Note that systemd is available only from the Jessie versions of Raspbian OS.
sudo nano /lib/systemd/system/fan_control.service
sudo chmod 644 /lib/systemd/system/fan_control.service
sudo systemctl daemon-reload
sudo systemctl enable fan_control.service
sudo reboot