Vagrant Optimize

* git status Optimize
* Change share's folder type to NSF
* Enable private_network
* Install some packages in Host Machine:
  $ sudo apt-get install nfs-kernel-server
  $ sudo apt-get install nfs-common
  $ sudo apt-get install cachefilesd

Reference links:
http://chase-seibert.github.io/blog/2014/03/09/vagrant-cachefilesd.html
https://help.ubuntu.com/12.04/serverguide/network-file-system.html
https://coderwall.com/p/uaohzg