More README info

README.md

@@ -22,3 +22,30 @@ option:
     docker rm apache
     docker run --name=apache -p=80:80/tcp --restart=always apache:latest
 
+## What's supported
+
+At present docker-rerun supports a small number of commonly used arguments:
+
+    * Names (--name)
+    * Networks (--net)
+    * Port publications (-p)
+    * Restart policies (--restart)
+    * Volumes (-v/--volume, and --volumes-from)
+
+## What's not done yet
+
+Many other command line arguments:
+
+    * Commands
+    * Environment variables
+    * Labels
+    * Linking and aliases
+    * Permissions and policies
+
+Additional options to allow mutating the container config when rerunning.
+For example:
+
+    $ ./docker-rerun --image nginx:1.11.1 nginx
+
+Should replace the previously used image with the one specified.
+