Added vagrant file and bootstrap script

Added vagrant file ‘Vagrantfile’.
Added bootstrap script ‘vagrant/bootstrap.sh’.
Updated README so developers know how to set up the environment.
Updated .gitignore to prevent committing vagrant cache.
Moved vagrant help to VAGRANT.md
Removed vagrant setup from README
Added company and user seed

This enables to set up a user to log in by executing `bin/rake db:seed`.
Merge pull request #10 from baswenneker/master

Created Vagrant File and bootstrap script for local development