Improved readme and added host variable for python interpreter

Signed-off-by: Jim Martens <github@2martens.de>

README.md

@@ -7,10 +7,25 @@ Contains ansible playbooks to set up VPS instances.
 A virtual host installed with Ubuntu Server 18. You will need the root password initially.
 You should have a password for the new SSH login user ready.
 
+Technical dependencies on host machine (Python 2.7 or 3.5+):
+
+* python / python3
+* python-pip / python3-pip
+* python-apt / python3-apt
+
+Technical dependencies on managed machines:
+
+* python / python3
+
+Install further dependencies on the host machine: ``pip install -r requirements.txt``
+
 ## Usage
 
 After cloning the repo to your ansible host, copy hosts.example to hosts and 
-fill the file appropriately. As of now Ubuntu Server 18 installations are expected.
+fill the file appropriately. If you use Python 3 on the managed machine, you probably
+need to adapt the ``ansible_python_interpreter`` variable.
+
+As of now Ubuntu Server 18 installations are expected.
 
 * initial setup: ``ansible-playbook -i hosts initial-setup.yml --ask-pass``
 * collabora setup: ``ansible-playbook -i hosts collabora.yml``

hosts.example

@@ -1,2 +1,2 @@
 [vps]
-vps123456.ovh.net
+vps123456.ovh.net ansible_python_interpreter=/usr/bin/python

requirements.txt

@@ -0,0 +1 @@
+passlib