## Steps to install packages within docker container; as an example, we need imageMagick with jekyll_picture_tag plugin to convert images in required format.
# 0. After docker & docker-compose have been setup and running with JEKYLL
# 1. (discover container ID's & copy ID for step 3) docker container ls --all
# 2. (in relative jekyll website directory) docker-compose up
# 3. (While docker container is running, sh into docker image) Open new terminal > docker exec -ti e1906de4a037 /bin/sh (Note: replace container ID with yours)
# 4. (Once logged into the Docker container RUN) apk --update add imagemagick
# 5. (Verify package has been installed) convert --version
# 6. Test jekyll_picture_tag plugin via {% picture test.jpg %}