Update README.md

README.md

 # RelAST Preprocessor
 
-Run preprocessor on train benchmark (output written to standard output)
+Run preprocessor on train benchmark (output written to standard output):
 
 	$ ant jar
+	$ cat examples/TrainBenchmark.relast
 	$ java -jar relast-compiler.jar examples/TrainBenchmark.relast
 
-Run preprocessor and write to files
+Run preprocessor and write output to files:
 
 	$ java -jar relast-compiler.jar examples/TrainBenchmark.relast --file
 	$ cat examples/TrainBenchmarkGen.ast
 	$ cat examples/TrainBenchmarkGen.jadd
 
-Run test cases
+Run test cases:
 
 	$ cd test
-	$ make
\ No newline at end of file
+	$ make
+
+Supported relations:
+
+	// Directed relations
+	A.b    -> B;
+	A.b?   -> B;
+	A.bs*  -> B;
+
+	// Bidirectional relations
+	A.b   <-> B.a;
+	A.b   <-> B.a?;
+	A.b   <-> B.as*;
+	A.b?  <-> B.a;
+	A.b?  <-> B.a?;
+	A.b?  <-> B.as*;
+	A.bs* <-> B.a;
+	A.bs* <-> B.a?;
+	A.bs* <-> B.as*;