Create a user guide

Our docs are very developer focused. Lets create a separate user guide
to help new users get started.

Change-Id: I8a03920e6d3306dd0405177875ea55ccb4b40fea

doc/source/developer/index.rst

@@ -0,0 +1,12 @@
+Developer Documentation
+=======================
+
+.. toctree::
+   :maxdepth: 2
+
+   design
+   components
+   invocation
+   caches
+   install_types
+   developing_elements

doc/source/index.rst

@@ -13,14 +13,7 @@ easier.
 
 .. toctree::
    :maxdepth: 2
-   
-   design
-   components
-   installation
-   invocation
-   caches
-   install_types
-   developing_elements
-   elements
-   copyright
 
+   user_guide/index
+   developer/index
+   elements

doc/source/user_guide/building_an_image.rst

@@ -0,0 +1,42 @@
+Building An Image
+=================
+
+Now that you have diskimage-builder properly :doc:`installed <installation>`
+you can get started by building your first disk image.
+
+VM Image
+--------
+
+Our first image is going to be a bootable vm image using one of the standard
+supported distribution :doc:`elements <../elements>` (Ubuntu or Fedora).
+
+The following command will start our image build (distro must be either
+'ubuntu' or 'fedora'):
+
+::
+
+    disk-image-create <distro> vm
+
+This will create a qcow2 file 'image.qcow2' which can then be booted.
+
+Elements
+--------
+
+It is important to note that we are passing in a list of
+:doc:`elements <../elements>` to disk-image-create in our above command. Elements
+are how we decide what goes into our image and what modifications will be
+performed.
+
+Some elements provide a root filesystem, such as the ubuntu or fedora element
+in our example above, which other elements modify to create our image. At least
+one of these 'distro elements' must be specified when performing an image
+build. It's worth pointing out that there are many distro elements (you can even
+create your own), and even multiples for some of the distros. This is because
+there are often multiple ways to install a distro which are very different.
+For example: One distro element might use a cloud image while another uses
+a package installation tool to build a root filesystem for the same distro.
+
+Other elements modify our image in some way. The 'vm' element in our example
+above ensures that our image has a bootloader properly installed. This is only
+needed for certain use cases and certain output formats and therefore it is
+not performed by default.

doc/source/user_guide/index.rst

@@ -0,0 +1,8 @@
+User Guide
+==========
+
+.. toctree::
+   :maxdepth: 1
+
+   installation
+   building_an_image