Add the beginings of a roadmap and faq

Needs expansion, but got to start somewhere...

Signed-off-by: Justin Cormack <justin.cormack@docker.com>

docs/faq.md

@@ -0,0 +1,32 @@
+# FAQ
+
+Please open an issue if you want to add a question here.
+
+## How do updates work?
+
+Moby does not require being installed on a disk, it is often run from an ISO, PXE or other
+such means, so it does not require an on disk upgrade method such as the ChromeOS code that
+is often used. It would definitely be possible to use that type of upgrade method if the 
+system is installed, and it would be useful to support this for that use case, and an
+updater container to control this for people who want to use this.
+
+We generally use external tooling such as [Infrakit](https://github.com/docker/infrakit) or
+CloudFormation templates to manage the update process externally from Moby, including
+doing rolling cluster upgrades to make sure distributed applciations stay up and responsive.
+
+Updates may preserve the state disk used by applications if needed, either on the same physical
+node, or by reattaching a virtual cloud volume to a new node.
+
+## What do I need to build Moby?
+
+We have tried to make this as simple as possible, by using containers for the build process, so
+you should be able to build Moby on any OSX or Linux laptop; we should have Windows build support
+soon.
+
+## Why not use `systemd`?
+
+In order to keep the system minimal, `systemd` did not seem appropriate, as it brings in a lot
+of dependencies and functionality that we do not need. At present we are using the `busybox`
+`init` process, and a small set of minimal scripts, but we expect to replace that with a small
+standalone `init` process and a small piece of code to bring up the system containers where the
+real work takes place.