design: add aws section to cloud agents

Add design decisions from #66

Design.md

@@ -13,7 +13,7 @@ conclusion should be summarized here with a link to the issue.
 
 ## OSTree Delivery Format
 
-- Originally discussed in issue [#23](https://github.com/coreos/fedora-coreos-tracker/issues/23). 
+- Originally discussed in issue [#23](https://github.com/coreos/fedora-coreos-tracker/issues/23).
 
 ### Summary:
 
@@ -24,7 +24,7 @@ end user systems:
   repo) on a server and fetched via HTTP requests.
 - rojig: uses a special rojig RPM and re-assembles OSTree commit from RPMs
   already on mirrors.
-- OCI: OSTree commits are packaged up in OCI container images and delivered 
+- OCI: OSTree commits are packaged up in OCI container images and delivered
   via a container registry.
 
 Currently the plan in Fedora CoreOS is to deliver content via a plain
@@ -78,7 +78,7 @@ Because production refs are unversioned, users will seamlessly upgrade between F
 
 ## Disk Layout
 
-- Originally discussed in issue [#18](https://github.com/coreos/fedora-coreos-tracker/issues/18). 
+- Originally discussed in issue [#18](https://github.com/coreos/fedora-coreos-tracker/issues/18).
   See also [dustymabe's comment](https://github.com/coreos/fedora-coreos-tracker/issues/18#issuecomment-409668929)
   summarizing the discussion in the FCOS meeting.
 - Filesystem details were discussed in [#33](https://github.com/coreos/fedora-coreos-tracker/issues/33).
@@ -174,6 +174,13 @@ Originally discussed in [#12](https://github.com/coreos/fedora-coreos-tracker/is
  - For the short term, if we need to include an agent we will bake it into the image. We will not have any specific
    mechanism for including agents.
 
+### AWS:
+
+Originally discussed in [#66](https://github.com/coreos/fedora-coreos-tracker/issues/66).
+
+- AWS does not require a cloud agent but does require NVME EBS udev rules
+- The udev rules and script will be packaged in an RPM and included in FCOS with work being tracked in [#104](https://github.com/coreos/fedora-coreos-tracker/issues/104)
+
 ### Azure:
 
 Originally discussed in [#65](https://github.com/coreos/fedora-coreos-tracker/issues/65).