docs: Add README

Relates to #1 .

README.md

@@ -1,41 +1,94 @@
-Role Name
-=========
+# Ansible Role for Uninstalling Moodle
 
 [![build](https://github.com/geoffreyvanwyk/ansible-role-moodle_uninstall/workflows/Build/badge.svg?event=push)](https://github.com/geoffreyvanwyk/ansible-role-moodle_uninstall/actions?query=workflow%3ABuild)
 
-A brief description of the role goes here.
+Uninstalls a Moodle instance by:
 
-Requirements
-------------
+* removing included Apache web server configuration,
+* removing cron job,
+* dropping database,
+* deleting the moodledata directory, and
+* deleting the Moodle source code from the web document root.
+
+## Requirements
 
 > Any pre-requisites that may not be covered by Ansible itself or the role
 > should be mentioned here. For instance, if the role uses the EC2 module, it may
 > be a good idea to mention in this section that the boto package is required.
 
-...
+The role only uninstalls a Moodle instance served from a subdirectory, and works best when the Moodle instance was installed with [Ansible role for Moodle](https://github.com/geoffreyvanwyk/ansible-role-moodle).
+
+The role is only tested on long-term support versions of Ubuntu that still receive standard support.
+
+At the moment, the role only uses Apache web server which it installs itself.
 
-Role Variables
---------------
+The role only supports removing the included Apache web configuration as for a Moodle instance installed in a subdirectory; not the removal of a virtual host configuration.
+
+## Role Variables
 
 > A description of the settable variables for this role should go here,
 > including any variables that are in defaults/main.yml, vars/main.yml, and any
 > variables that can/should be set via parameters to the role. Any variables that
 > are read from other roles and/or the global scope (ie. hostvars, group vars,
 > etc.) should be mentioned here as well.
 
-...
+### Deployment of Source Code
+
+```yaml
+moodle_deploy_destination: /var/www/html/moodle
+```
+
+The path to the Moodle source code.
+
+---
+
+### Set-Up of Database
+
+```yaml
+moodle_cfg_dbtype: pgsql # Which database service is used: pgsql or maridb.
+moodle_cfg_dbname: moodle # The name of the database.
+moodle_cfg_dbuser: # Username.
+moodle_cfg_dbpass: # Password.
+```
+
+The database user provided must have permission to drop the database. If no username and password are given, for PostgreSQL, the `postgres` user will be used; for MariaDB, the socket will be used, if possible.
+
+---
+
+### Web Hosting
+
+```yaml
+moodle_web_domain: 127.0.0.1 # Domain name of the web service virtual host.
+moodle_web_path: moodle # Subdirectory relative to virtual host.
+```
+
+As with the Ansible role for Moodle, These two variables are used to calculate the `moodle_instance` variable that uniquely identifies the Moodle instance. The `moodle_instance` variable is used to:
+
+* locate the moodledata directory, unless that path is explicitly given;
+* locate the included Apache configuration file;
+* identify the cronjob that needs to be removed.
+
+If the `moodle_web_path` is not given, it is calculated from the basename `moodle_deploy_destination`.
+
+---
+
+### Installation & Server-Side configuration
+
+```yaml
+moodle_cfg_dataroot: /var/www/moodledata
+```
+
+The path to the moodledata directory. If not given, it is calculated from the `moodle_instance` variable.
 
-Dependencies
-------------
+## Dependencies
 
 > A list of other roles hosted on Galaxy should go here, plus any details in
 > regards to parameters that may need to be set for other roles, or variables that
 > are used from other roles.
 
-...
+The list of roles on which this role depends can be found in `requirements.yml` .
 
-Example Playbook
-----------------
+## Example Playbook
 
 > Including an example of how to use your role (for instance, with variables
 > passed in as parameters) is always nice for users too:
@@ -44,11 +97,10 @@ Example Playbook
 - hosts: servers
  roles:
  - role: geoffreyvanwyk.moodle_uninstall
- x: 42
+ moodle_web_domain: www.example.com
 ```
 
-License
--------
+## License
 
 Copyright © 2023 Geoffrey Bernardo van Wyk [https://geoffreyvanwyk.dev](https://geoffreyvanwyk.dev)
 
@@ -67,8 +119,7 @@ Public License for more details.
 You should have received a copy of the GNU General Public License along with
 Ansible role geoffreyvanwyk.moodle_uninstall. If not, see <https://www.gnu.org/licenses/>.
 
-Author Information
-------------------
+## Author Information
 
 > An optional section for the role authors to include contact information, or a
 > website (HTML is not allowed).