README: Add content

Signed-off-by: Tom Siewert <[email protected]>

README.md

@@ -1,3 +1,36 @@
 # Ansible Role - iPXE CA
 
-Cross-sign Root CAs with your own CA for iPXE.
+An Ansible role to cross-sign all Root CAs with your own CA for iPXE.
+
+## Requirements
+
+* Ansible
+* CA used for cross-signing
+
+## Role Variables
+
+``` yaml
+ipxe_ca__web_path: '/var/www/ca'
+
+ipxe_ca__ca_cert_path: '/etc/ssl/private/ipxe.crt'
+ipxe_ca__ca_key_path: '/etc/ssl/private/ipxe.key'
+
+ipxe_ca__certificate_valid_days: 180
+ipxe_ca__systemd_timer_enabled: true
+```
+
+## Dependencies
+
+None.
+
+## Example Playbook
+
+``` yaml
+- hosts: all
+  roles:
+    - hetzner.ipxe_ca
+```
+
+## License
+
+GPL-3.0