Added a script for easily maintaining the project.

This is a script that will make our lives easier with maintaining the project. There are more to come, but for now we can deploy to multiply places using this script:

# Deploy locally (localhost:8080)
hl deploy dev

# Deploy to staging (care-tiger-staging.appspot.com)
hl deploy staging

# Deploy to prod (care-tiger.appspot.com)
hl deploy prod