This Dockerfile is setup for symfony 1.4.x and sendgrid you should change file below:
files/app.yml
files/factories_yml.sh
change SENDGRID_USERNAME and SENDGRID_PASSWORD
files/index.php
change sender@sender@.com and recipient@recipient.com
after that execute ./build.sh and ./run.sh
run.sh start sshd. You can access to the container via ssh. You need inspect IP address of the container.