doc: update README

README.org

 #+TITLE: Collection of ansible playbooks for cluster management
 
+* Installing guix
+
+To install guix run the corresponding playbook:
+
+#+begin_src bash
+  ansible-playbook install_guix.yaml -i hosts
+#+end_src
+
+This does need root access on the cluster.
+
 * Installing software
 
 To install software, run the corresponding playbook
@@ -8,7 +18,7 @@ To install software, run the corresponding playbook
   ansible-playbook install_software.yaml -i hosts
 #+end_src
 
-This needs root access on the cluster.
+This does not need root access on the cluster.
 
 * Hosts
 
@@ -20,12 +30,12 @@ master will be mounted on all the nodes.
 * Software
 
 Software managed through this repository can be found in the yaml file
-[[cluster_config/software.yaml]]. This is the definite answer to which
-version is installed on the cluster.
-Installation paths are configured in [[cluster_config/installation.yaml]].
+[[software.yaml]]. This is the definite answer to which version is
+installed on the cluster.  Installation paths are configured in
+[[installation.yaml]].
 
 * Module files
 
 Each installed software has an accompanying module file. They are
-separated in ~/opt/modules/guix~ (for FOSS software) and
-~/opt/modules/prop~ (for proprietary software).
+separated in ~guix~ (for FOSS software) and ~prop~ (for proprietary
+software).