Update README.md

Author: rustyrazorblade

README.md

@@ -4,3 +4,12 @@ Cassandra Dataset Manager, referred to simply as `cdm`, is a tool to learn how t
 
 Work in progress.  Original cdm was written in Python but is being ported to Java for maintainability and the ability to easy distribute a single file.
 
+## Building
+
+You can build an executable via the following command:
+
+`src/main/sh/build_runnable.sh`
+
+This will create a JAR with a bash wrapper that you can drop in your $PATH and run like a normal Linux/Mac executable.
+
+CDM doesn't currently work on windows as it's dependent on bash and cqlsh.  There are plans to lift this restriction.