Make tests for each docker build in this repo

[LuisAlejandro]

Based on #112, each image should be tested for a common set of tasks:

• Is every software listed on the definition available and behaving correctly?
• Can we make basic operations on the OS? (Install/uninstall software, restart services, uncompress archives, etc).
• Is the performance OK?

[LuisAlejandro]

I've been implementing this feature on my docker images using rspec and serverspec (ruby) because its dead simple.

Here you have some resources to start:

• https://robots.thoughtbot.com/tdd-your-dockerfiles-with-rspec-and-serverspec
• http://www.unixdaemon.net/tools/testing-dockerfiles-with-serverspec/

[moylop260]

Thank you I'll review it the next week

[LuisAlejandro]

I've implemented this on my own images, you can check out my test script for a debian image here: https://github.com/LuisAlejandro/dockershelf/blob/develop/debian/test-image.rb

And how to run it here: https://github.com/LuisAlejandro/dockershelf/blob/develop/test-image.sh#L43

And here: https://github.com/LuisAlejandro/dockershelf/blob/develop/.travis.yml#L53

I've also made a test script for python images, but it's not complete yet: https://github.com/LuisAlejandro/dockershelf/blob/develop/python/test-image.rb

Greetings!