Docs: Adding accessbot info to the IRC services page

Documentation points to gerribot but it does not mention about
accessbot while creating and setting IRC services for a given
project.

Change-Id: I974bff563e9142b050024023d8494da5826c3ef3

doc/source/irc.rst

@@ -23,6 +23,7 @@ At a Glance
   * :file:`modules/openstack_project/manifests/review.pp`
 :Configuration:
   * :config:`gerritbot/channels.yaml`
+  * :config:`accessbot/channels.yaml`
 :Projects:
   * http://wiki.debian.org/MeetBot
   * http://sourceforge.net/projects/supybot/
@@ -54,6 +55,9 @@ your channel.
 
 Join #openstack-infra if you have any trouble with any of these commands.
 
+NOTE: Channel admin should issue the access commands above BEFORE adding
+channel to gerritbot and accessbot, otherwise Jenkins will fail tests.
+
 Meetbot
 =======
 
@@ -212,6 +216,24 @@ Teams can add their channel and go through the standard code review process to
 get the bot added to their channel. The configuration is organized by channel,
 with each project that a channel is interested in listed under the channel.
 
+.. _accessbot:
+
+Accessbot
+=========
+
+Accessbot defines access that should apply to all channels. Teams can add new
+channel to accessbot/channels.yaml and optionally keep channel operator
+permissions to the channel by specifying the full_mask option.
+
+Accessbot's configuration is in :config:`accessbot/channels.yaml`
+
+Example:
+
+::
+
+  - name: openstack-third-party-ci
+    mask: full_mask
+
 Basic Channel Operator Commands
 ===============================