i) Download all 3 files into local directory
ii) Rename Dockerfile to Dockerfile.web
iii) Rename Dockerfile.tomcat to Dockerfile.

# docker build -t tomcat:8.0 .
# docker run -d --name tomcat tomcat:8.0

iv) Rename Dockerfile to Dockerfile.tomcat
v) Rename Dockerfile.web to Dockerfile

# docker build -t web:1.0 .
# docker run -d --name tomcat -p 80:80 web:1.0