Update tools README file

tools/model_generator_dotnet/README.md

@@ -3,6 +3,10 @@ To run the tool from the command line a command of the following format has to b
 
 <generator option> <ICD file>  -ied  <ied-name> -ap <access-point-name> -out <output-name> -modelprefix <model-prefix>
 
+Usage:
+Static Model (1)
+Dynamic Model (2)
+
 The values in <> have to be replaced with the values corresponding to an arbitrary ICD file. 
 To run this command completely the command should look like this: