Add a FAQ and link to it from the README (#123)

* Added a FAQ and linked to it from the README

* Address review comments

README.md

@@ -12,6 +12,8 @@ AKS-Engine leverages ARM (Azure Resource Manager) to build Kubernetes IaaS in Az
 
 We are currently in transition from acs-engine to aks-engine! Bear with us as we stabilize this space as the future home for building customizable, self-managed Kubernetes on Azure!
 
+Please see the [FAQ](/docs/faq.md) for answers about AKS-Engine and this project transition.
+
 ## Code of conduct
 
 This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/). For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq) or contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any additional questions or comments.

docs/faq.md

@@ -0,0 +1,35 @@
+# AKS-Engine FAQ
+
+This page provides help with the most common questions about AKS-Engine.
+
+### What's the Difference Between AKS and AKS-Engine?
+
+Azure Kubernetes Service ([AKS][]) is a Microsoft Azure service that supports fully managed Kubernetes clusters. [AKS-Engine][] is an Azure open source project that creates Kubernetes clusters with your custom requirements. AKS uses AKS-Engine internally, but they are not the same.
+
+AKS clusters can be created in the Azure portal or with `az aks create` in the [Azure command-line tool][]. AKS-Engine clusters can be created with `aks-engine deploy` in the AKS-Engine command-line tool, or by generating the ARM templates with `aks-engine generate` and deploying them as a separate step.
+
+### What's the Difference Between `acs-engine` and `aks-engine`?
+
+AKS-Engine is the next version of the ACS-Engine project. AKS-Engine supports current and future versions of [Kubernetes][], while ACS-Engine also supported the Docker Swarm and Mesos DC/OS container orchestrators.
+
+### Can I Scale or Upgrade an `acs-engine` Cluster with `aks-engine`?
+
+Yes.
+
+### Is ACS-Engine Still Active?
+
+No further development or releases in ACS-Engine are planned. AKS-Engine is a backward-compatible continuation of ACS-Engine, so all fixes and new features will target AKS-Engine.
+
+### Can I Build an AKS Cluster with `aks-engine`?
+
+No, Azure Kubernetes Service itself is the way to create a supported, managed AKS cluster. AKS-Engine shares some code with AKS, but does not create managed clusters.
+
+### Where is the `aks-engine` Release?
+
+We don't have an official aks-engine release yet. Please use the most recent [acs-engine release][] for now.
+
+[AKS]: https://azure.microsoft.com/en-us/services/kubernetes-service/
+[AKS-Engine]: https://github.com/Azure/aks-engine
+[Azure command-line tool]: https://docs.microsoft.com/en-us/cli/azure/install-azure-cli?view=azure-cli-latest
+[acs-engine release]: https://github.com/Azure/acs-engine/releases
+[Kubernetes]: https://kubernetes.io/