Added a description field

can be useful to provide some extensive descriptions of a scenario

accurest-core/src/main/groovy/io/codearte/accurest/dsl/GroovyDsl.groovy

@@ -17,6 +17,7 @@ class GroovyDsl {
 	Request request
 	Response response
 	String label
+	String description
 	Input inputMessage
 	OutputMessage outputMessage
 
@@ -35,6 +36,10 @@ class GroovyDsl {
 		this.label = label
 	}
 
+	void description(String description) {
+		this.description = description
+	}
+
 	void request(@DelegatesTo(Request) Closure closure) {
 		this.request = new Request()
 		closure.delegate = request