updated docs with better example
updated docs with better example

leisms/grunt-harness,GabrielNicolasAvellaneda/grunt-mocha-test,sergeydt/grunt-mocha-test,GabrielNicolasAvellaneda/grunt-mocha-test,sergeydt/grunt-mocha-test,pghalliday/grunt-mocha-test,sergeydt/grunt-mocha-test