Change the Vagrant basebox url in the CONTRIBUTING.md
Remove cache directories from vagrant NFS sync
Merge pull request #22 from akosednar/patch-3

Remove cache directories from vagrant NFS sync
[skip ci] Updated the Readme and contributing guidance to ask people remember to [skip ci] if their commit doesn't touch app code
[skip ci] Link to contributing.md from readme
[skip ci] Fixed link to contributing.md from readme