update README.md with instructions to run fitnesse and unit tests from IntelliJ IDE

[wpannell]

Would be a time saver for those of us who would have to figure out how to follow the screencast without the required tools already in our back pocket.

[abd3lraouf]

I think you can download fitnesse and launch it using the following command

1. cd to project dir
2. download fitnesse-standalone.jar and put it in project dir.
3. run the command java -jar <fitnesse-standalone.jar> -p <8080> Note the last dot.

where
<fitnesse-standalone.jar> is the jar file name you downloaded from Fitnesse site
<8080> is port number

Example
java -jar fitnesse-standalone.jar -p 8080

Also you can watch this video by Uncle Bob himself about Fitnesse

Good luck