Add coafile
Add coafile

This allows using coala to check this code.

iamshubh22/babel,python-babel/babel,srisankethu/babel,srisankethu/babel,mitsuhiko/babel,python-babel/babel,mitsuhiko/babel,iamshubh22/babel,mitsuhiko/babel,srisankethu/babel,iamshubh22/babel