Add information about host's Docker configuration (#184)

* Add information about host's Docker configuration

* Move Docker block to its own file

* Fix configuration mistake

README.md

@@ -116,7 +116,7 @@ Read more on [logging](docs/logging.md).
 
 ## Writing Functions
 
-TODO: 
+TODO:
 
 ## More Documentation
 

docs/README.md

@@ -10,3 +10,4 @@
 * [Metrics](metrics.md)
 * [Triggers](triggers.md)
 * [Extending IronFunctions](extending.md)
+* [Docker Configuration](docker.md)

docs/docker.md

@@ -0,0 +1,21 @@
+# Docker Configuration
+
+To get the best performance, you'll want to ensure that Docker is configured properly. These are the environments known to produce the best results:
+
+1) Linux 4.7 or newer with Overlay2 module
+2) Ubuntu 16.04 LTS or newer with Overlay2 module
+3) Docker 1.12 or newer to be available
+
+It is important to reconfigure host's Docker with this filesystem module. Thus, in your Docker start scripts you must do as following:
+
+```
+docker daemon [...] --storage-driver=overlay2
+```
+
+In case you are using Ubuntu, you can reconfigure Docker easily by updating `/etc/docker/daemon.json` and restarting Docker:
+
+```json
+{
+    "storage-driver": "overlay2"
+}
+```