My addition to /etc/fstab was:
# zram swap /dev/zram0
/dev/disk/by-uuid/7A7E1892271D8139 /mnt/7A7E1892271D8139 auto nosuid,nodev,nofail,x-gvfs-show,noauto 0 0
(and I disabled my swap partition)
Because of this: Linux Performance: Almost Always Add Swap Space - Part 2: ZRAM
and it did exactly what I wanted it to do. 
It was conveniently automatically added when setting up zram.
(otherwise I would have done it myself 
)