Add Dockerfile for automated build

[pascalgrimaud]

Related to jhipster/generator-jhipster#4119

The Docker Hub project is already configured: https://hub.docker.com/r/jhipster/jhipster-sample-app/

@jdubois : before merging this, can you:

• Go to settings > Webhooks & services
• Verify the services: Docker => edit
• Click [x] active
• Click on update service
• Then, accept PR if you're ok :-)
• Back to Services, Docker must be: ✅ Docker

Thanks in advance!

[jdubois]

Done! I hope the webhook will work!

[pascalgrimaud]

Thanks Julien, it works! -> https://hub.docker.com/r/jhipster/jhipster-sample-app/builds/
I will test tonight the image

[pascalgrimaud]

Just tested this image on my windows machine at work, and it works perfectly!
docker run -p 8080:8080 -e SPRING_PROFILES_ACTIVE=dev jhipster/jhipster-sample-app:master

Very good news! Thanks @jdubois