The frontend build requires around 8GB of memory to be assigned to docker to build. If you run into this, bump your docker memory allocation up to 9GB or more.
How to push to docker hub:
docker tag local-image:tagname dagworks/ui-backend:LATEST docker push dagworks/ui-backend:LATEST
docker tag local-image:tagname dagworks/ui-frontend:LATEST docker push dagworks/ui-frontend:LATEST