Minor updates to Vagrantfile

- Add license header

- Let setup.py decide the Python interpreter to use

- Don't make a copy of the project directory making it easier to
  re-provision.

- Show a message on how to proceed after bringing up the VM

Vagrantfile

@@ -1,13 +1,34 @@
 # -*- mode: ruby -*-
 # vi: set ft=ruby :
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
 Vagrant.configure(2) do |config|
   config.vm.box = "jvalleroy/plinth-dev"
   config.vm.network "forwarded_port", guest: 443, host: 4430
   config.vm.provision "shell", inline: <<-SHELL
-    cp -R /vagrant /home/vagrant/plinth
-    cd /home/vagrant/plinth
-    python3 setup.py install
+    cd /vagrant/
+    ./setup.py install
     systemctl daemon-reload
     systemctl restart plinth
   SHELL
+  config.vm.post_up_message = "FreedomBox machine is ready for Plinth development.
+You can access it on https://localhost:4430/plinth/ (with an invalid
+SSL certificate). You can modify source code on the host machine and
+then test it by running:
+$ vagrant provision
+"
 end