Update docs for Etherpad Lite Puppet module.

Puppet module to manage Etherpad Lite has been merged into this repo
and needs to be documented. New documentation for the module included.

Change-Id: I1b818723bc8233c5f1b536780cde43c5be9374c3

doc/puppet_modules.rst

@@ -268,9 +268,118 @@ enter
 in the ``JS`` box enter
 ``https://jenkins.openstack.org/plugin/simple-theme-plugin/openstack.js``.
 
+Etherpad Lite
+-------------
+
+This Puppet module installs Etherpad Lite [6]_ and its dependencies (including
+node.js). This Puppet module also configures Etherpad Lite to be started at
+boot with Nginx running in front of it as a reverse proxy and MySQL running as
+the database backend.
+
+Using this module is straightforward you simply need to include a few classes.
+However, there are some limitations to be aware of which are described below.
+The includes you need are:
+
+::
+
+  include etherpad_lite        # Acts like a package manager and installs things
+  include etherpad_lite::nginx # Sets up Nginx to reverse proxy Etherpad Lite
+  include etherpad_lite::site  # Configures Etherpad Lite
+  include etherpad_lite::mysql # Configures MySQL DB backend for Etherpad Lite
+
+These classes are parameterized and provide some configurability, but should
+all work together when instantiated with their defaults.
+
+Config File
+^^^^^^^^^^^
+
+Because the Etherpad Lite configuration file contains a database password it is
+not directly managed by Puppet. Instead Puppet expects the configuration file
+to be at ``/root/secret-files/etherpad-lite_settings.json`` on the Puppet
+master (if running in master/agent setup) or on the server itself if running
+``puppet apply``.
+
+MySQL will be configured by Puppet to listen on TCP 3306 of localhost and a
+database called ``etherpad-lite`` will be created for user ``eplite``. Also,
+this module does install the Abiword package. Knowing this, a good template for
+your config is: 
+
+::
+
+  /*
+    This file must be valid JSON. But comments are allowed
+  
+    Please edit settings.json, not settings.json.template
+  */
+  {
+    //Ip and port which etherpad should bind at
+    "ip": "127.0.0.1",
+    "port" : 9001,
+    
+    //The Type of the database. You can choose between dirty, sqlite and mysql
+    //You should use mysql or sqlite for anything else than testing or development
+    "dbType" : "mysql",
+    //the database specific settings
+    "dbSettings" : {
+                     "user"    : "eplite", 
+                     "host"    : "localhost", 
+                     "password": "changeme", 
+                     "database": "etherpad-lite"
+                   },
+    
+    //the default text of a pad
+    "defaultPadText" : "Welcome to Etherpad Lite!\n\nThis pad text is synchronized as you type, so that everyone viewing this page sees the same text. This allows you to collaborate seamlessly on documents!\n\nEtherpad Lite on Github: http:\/\/j.mp/ep-lite\n",
+    
+    /* Users must have a session to access pads. This effectively allows only group pads to be accessed. */
+    "requireSession" : false,
+  
+    /* Users may edit pads but not create new ones. Pad creation is only via the API. This applies both to group pads and regular pads. */
+    "editOnly" : false,
+    
+    /* if true, all css & js will be minified before sending to the client. This will improve the loading performance massivly, 
+       but makes it impossible to debug the javascript/css */
+    "minify" : true,
+  
+    /* How long may clients use served javascript code? Without versioning this
+      is may cause problems during deployment. */
+    "maxAge" : 21600000, // 6 hours
+    
+    /* This is the path to the Abiword executable. Setting it to null, disables abiword.
+       Abiword is needed to enable the import/export of pads*/  
+    "abiword" : "/usr/bin/abiword",
+    
+    /* This setting is used if you need http basic auth */
+    // "httpAuth" : "user:pass",
+  
+    /* The log level we are using, can be: DEBUG, INFO, WARN, ERROR */
+    "loglevel": "INFO"
+  }
+
+Don't forget to change the password if you copy this configuration. Puppet will
+grep that password out of the config and use it to set the password for the
+MySQL eplite user.
+
+Nginx
+^^^^^
+
+The reverse proxy is configured to talk to Etherpad Lite over localhost:9001.
+Nginx listens on TCP 443 for HTTPS connections. Because HTTPS is used you will
+need SSL certificates (again not managed by Puppet because of the sensitive
+nature of these files). Nginx expects your certificate file to be at
+``/etc/nginx/ssl/eplite.crt`` and your certificate key file to be at
+``/etc/nginx/ssl/eplite.key``.
+
+MySQL
+^^^^^
+
+MySQL is configured by the Puppet module to allow user ``eplite`` to use
+database ``etherpad-lite``. This module does not configure backups for the
+``etherpad-lite`` database.
+
 .. rubric:: Footnotes
 .. [1] `Lodgeit homepage <http://www.pocoo.org/projects/lodgeit/>`_
 .. [2] `Drizzle homepage <http://www.drizzle.org/>`_
 .. [3] `nginx homepage <http://nginx.org/en/>`_
 .. [4] `Planet Venus homepage <http://intertwingly.net/code/venus/docs/index.html>`_
 .. [5] `Meetbot homepage <http://wiki.debian.org/MeetBot>`_
+.. [6] `Etherpad Lite homepage <https://github.com/Pita/etherpad-lite>`_