Create dockerfiles/images for PHP7-beta and project

[Igor Santos]

We need a basic PHP7-beta image, since there's none on the web. We also need a custom-made image that will run our application.

[Igor Santos]

Using a more standard dockerfile (running service commands as CMD and not RUN) and cleaning up dirty in the project's dockerfile. refs #5

→ <<cset 9efce9bab005>>

[Igor Santos]

Adding heroku buildpack (could be used in the project's dockerfile later). refs #5

→ <<cset 8b3c8e6d61d0>>

[Igor Santos]

Adding a basic but working project dockerfile. closes #5

→ <<cset d4d95ecff64b>>