Add travis ci

@thanpolas I configured .travis,yml 

I tried it with my fork it works as a charm : https://travis-ci.org/xarisd/devit

I think we got Continuous Integration. 

Now we need Continuous Deployment :-) 

Fixes #2 
@thanpolas  : Do you think we need more or less node.js versions here? 
Be aware that travis-ci needs about  2 min 15 sec for each version.
(It DOES NOT create separate builds for the different Ruby versions)