1. Create Dockerfile.
2. docker build -t USERNAME/REPONAME .
3. docker push USERNAME/REPONAME
4. If you need to update Dockerfile, repeat steps 2 and 3.
5. If you want to make changes within the image:
   • Start the image:
     • docker run -d USERNAME/REPONAME bash
   • Enter the image and make changes:
     • docker exec -it CONTAINER
   • exit the container
   • Commit changes:
     • docker commit CONTAINER USERNAME/REPONAME
   • Push changes:
     • docker push USERNAME/REPONAME

Note: If using the included httpd Dockerfile you must run with something like -p 80:80 to map the ports properly.