Added missing builders to intro

website/source/intro/platforms.html.markdown

@@ -36,9 +36,18 @@ the appropriate [documentation page within the documentation section](/docs).
 * ***DigitalOcean***. Snapshots for [DigitalOcean](http://www.digitalocean.com)
   that can be used to start a pre-configured DigitalOcean instance of any size.
 
+* ***Docker***. Snapshots for [Docker](http://www.docker.io)
+  that can be used to start a pre-configured Docker instance.
+
+* ***Google Compute Engine***. Snapshots for [Google Compute Engine](https://cloud.google.com/products/compute-engine)
+  that can be used to start a pre-configured Google Compute Engine instance.
+
 * ***OpenStack***. Images for [OpenStack](http://www.openstack.org)
   that can be used to start pre-configured OpenStack servers.
 
+* ***QEMU***. Images for [KVM](http://www.linux-kvm.org/) or [Xen](http://www.xenproject.org/)
+  that can be used to start pre-configured KVM or Xen instances.
+
 * ***VirtualBox (OVF)***. Exported virtual machines for VirtualBox, including
   virtual machine metadata such as RAM, CPUs, etc. These virtual machines are
   portable and can be started on any platform VirtualBox runs on.