You can resize your droplet.
Swap is using part of your hard drive as RAM. You should have some already.
free -h
will show you ram and swap.
discourse-setup adds a 2gb swap partition like this:
install -o root -g root -m 0600 /dev/null /swapfile
fallocate -l 2G /swapfile
mkswap /swapfile
swapon /swapfile
echo "/swapfile swap swap auto 0 0" | tee -a /etc/fstab
sysctl -w vm.swappiness=10
You may already have 2GB and need to increase it. An easy way is to do those steps again, but change swapfile to swapfile2
If you’re frustrated and want to throw money at the problem, see my profile.