Added minimal vagrantfile

This makes an Ubuntu-based vagrant image that has
 - docker installed
 - go tools installed
 - weave dependencies installed
 - $GOPATH set to ~
 - the local working directory mapped as a synced folder into the
   right place in $GOPATH

So one should be able to

    $ vagrant up
    $ vagrant ssh
    vagrant$ cd src/github.com/zettio/weave
    vagrant$ make -C weaver

Vagrantfile

@@ -0,0 +1,23 @@
+VAGRANTFILE_API_VERSION = "2"
+
+vm_ip = "172.16.0.3" # arbitrary private IP
+pkgs = "docker.io golang ethtool libpcap-dev git mercurial"
+
+Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
+  config.vm.box = "phusion/ubuntu-14.04-amd64"
+  config.vm.box_url = "https://oss-binaries.phusionpassenger.com/vagrant/boxes/latest/ubuntu-14.04-amd64-vbox.box"
+  
+  config.vm.network "private_network", ip: vm_ip
+
+  config.vm.synced_folder "./", "/home/vagrant/src/github.com/zettio/weave"
+
+  pkg_cmd = "apt-get update -qq; " \
+  "apt-get install -q -y --force-yes --no-install-recommends "
+  pkg_cmd << pkgs
+  config.vm.provision :shell, :inline => pkg_cmd
+  config.vm.provision :shell, :inline => "usermod -a -G docker vagrant; "
+  config.vm.provision :shell, :inline => "echo export GOPATH=/home/vagrant >> /home/vagrant/.bashrc"
+  config.vm.provision :shell, :inline => "chown -R vagrant:vagrant /home/vagrant/src"
+  config.vm.provision :shell, :inline => "sudo go install -a -tags netgo std"
+
+end