OP#78 define is added and tested working

README.md

@@ -7,6 +7,7 @@
   - [Synopsis](#synopsis)
   - [WARNING](#warning)
   - [Features](#features)
+  - [Adding custom configurations](#adding-custom-configurations)
   - [Support](#support)
   - [Parameter Inheritance](#parameter-inheritance)
   - [Module Deployment](#module-deployment)
@@ -29,7 +30,29 @@
 - manage service
 - (optional) manage firewall
 
-> ToDo: Define for custom drop-in configurations
+## Adding custom configurations
+
+Custom configuration files live in  `/etc/ssh/sshd_config.d/`. IN order to create a custom config file, add a stanza like this in your control repo:
+
+```puppet
+confdroid_ssh::custom::custom_config { '30-my-custom-rule':
+  config_name    => '30-custom-rule',
+  config_content => ['PasswordAuthentication no'],
+}
+```
+
+This will create a file /etc/ssh/sshd_config.d/30-custom-rule.conf with this content:
+
+```puppet
+###############################################################################
+##### DO NOT EDIT THIS FILE MANUALLY                                          #
+##### This file is managed by Puppet. Any changes to this file will be        #
+##### overwritten. Update the Puppet define input instead.                    #
+###############################################################################
+PasswordAuthentication no
+```
+
+Note that the value for config_content **has to be an array**, even if only one key pair is in there. This field is designed to hold multiple values, which create one line in the config file each.
 
 ## Support