[todo] greatly extend todo list

TODO.md

@@ -9,6 +9,7 @@ description: Todo items in lists, and lists themselves, are not prioritised
     - [ ] create db schema and user for the django project
   - [ ] install some django project via git on "application_servers"
     - [ ] avoid using git&python as root
+    - [ ] use caddy server instead of nginx
   - [ ] allow "application_servers" to conntect to "database_servers"
     - [ ] `./manage.py check` should pass as well
   - [ ] make playbook available via "just deploy"
@@ -21,3 +22,17 @@ description: Todo items in lists, and lists themselves, are not prioritised
 
 - [ ] create backups (sql dump) or snapshot of postgres DB
   - [ ] make it available via "just backup"
+
+- [ ] install docker
+  - [ ] install some test image and run it
+
+- [ ] set up virtual machine stuff
+  - [ ] run some OS in such a VM
+    - VM in a VM: does that work on local test?
+  - [ ] change setup of that virtualised VM
+    - [ ] install a software and change its configuration (via ansible?)
+
+- [ ] deploy local Raspberry pi
+  - [ ] NAS
+  - [ ] media player
+  - [ ] pi hole