Clean your Tamagotchi

[rafaelhenrique]

Based on class described here:
https://groups.google.com/forum/#!topic/python-sorocaba/w2EvUun-NHQ

• Send your tamagotchi to take a shower, via post method
• Make sure it is clean with GET method

[rafaelhenrique]

One PR for this issue is only accepted if have tests and Coverage > 90%.