Allocate a 512M swap file in digital ocean linux droplet

By default Digital Ocean VPS instance is not configured to use swap space
login as root user, perform the following:
dd if=/dev/zero of=/swap.dat bs=1024 count=512K 
mkswap /swap.dat 
swapon /swap.dat 
#Edit the /etc/fstab, add the following entry. 
/swap.dat none swap sw 0 0