Update README.md

Author: KristianKarl

graphwalker-cli/README.md

@@ -1,3 +1,16 @@
 GraphWalker CLI 
 ======
 Documentation at http://graphwalker.org/docs/command_line_syntax
+
+### How to build the standalone jar of graphwalker-cli
+```bash
+git clone https://github.com/GraphWalker/graphwalker-project.git
+cd graphwalker-project
+mvn package -pl graphwalker-cli -am
+```
+
+The jar is in:
+```bash
+graphwalker-cli/target/graphwalker-cli-3.2.1.jar
+```
+