[gnome-builder] doc: add section on enabling/disabling extensions

[Christian Hergert <chergert src gnome org>]

commit f038a5d2564e6ad818766a6e68efff5305d87418
Author: Christian Hergert <chergert redhat com>
Date:   Wed Sep 6 14:32:34 2017 -0700

    doc: add section on enabling/disabling extensions

 doc/figures/extensions.png |  Bin 0 -> 232476 bytes
 doc/plugins/enabling.rst   |   29 +++++++++++++++++++++++++++++
 doc/plugins/index.rst      |    1 +
 3 files changed, 30 insertions(+), 0 deletions(-)
---
diff --git a/doc/figures/extensions.png b/doc/figures/extensions.png
new file mode 100644
index 0000000..09073b5
Binary files /dev/null and b/doc/figures/extensions.png differ
diff --git a/doc/plugins/enabling.rst b/doc/plugins/enabling.rst
new file mode 100644
index 0000000..dc2e37d
--- /dev/null
+++ b/doc/plugins/enabling.rst
@@ -0,0 +1,29 @@
+#################################
+Enabling and Disabling Extensions
+#################################
+
+Builder is built to be extensible from the ground up.
+In fact, many features of Builder are created as extensions.
+To customize Builder for your workflow you may want to enable or disable some extensions.
+
+To enable or disable an extension, use the perspective selector and navigate to "Preferences".
+You can also use the keyboard shortcut ``Control+,``.
+
+.. image:: ../figures/perspectives.png
+   :width: 295 px
+   :align: center
+
+You'll be presented with the preferences perspective which looks like:
+
+.. image:: ../figures/preferences.png
+   :width: 1284 px
+   :align: center
+
+Select "Extensions" from the menu on the left.
+Then use the switches on the right to enable or disable an extension.
+
+.. tip:: Use the search entry in the upper left to search for an extension
+
+.. image:: ../figures/extensions.png
+   :width: 1280 px
+   :align: center
diff --git a/doc/plugins/index.rst b/doc/plugins/index.rst
index 53dc938..6cf77a7 100644
--- a/doc/plugins/index.rst
+++ b/doc/plugins/index.rst
@@ -12,6 +12,7 @@ You may also chooser to implement extensions in C or Vala.
    :maxdepth: 3
    :titlesonly:
 
+   enabling
    creating
    workbench/index
    greeter