Updating rvmrc and validating invalid objects when are exposed

Little changes:

- Removing .rvmrc in favor of new convention
- Ignoring finder config files 
- Validating invalid objects when are exposed 

I know that should be used create! or validate the invalid objects before expose it, but in the case that invalid object was expose, the api shouldn't show a 200 status code, the method should validate that info and throwing an exception.