var/generation folder cannot be written to in magento2 on OS X using vagrant and boot2docker 1.7.1

[youanden]

This is in case other's come to experience this problem with permissions.

I followed the guide here

Feel free to put this in the README if you find it important enough. I am not sure if the docker beta will solve this issue as it promises to avoid using vagrant but until then it's a problem.

Thanks for this package!