Add version mapping

- Add version mapping

Author: Murray-LIANG

README.md

@@ -7,6 +7,13 @@ Dell EMC Unity Cinder driver
 exactly if you are upgrading Unity Cinder driver from version 0.4.1
 (and before), or newly installing Unity Cinder driver.**
 
+Version mapping
+---------------
+|       | Liberty | Mitaka | Newton | Ocata | Pike   |
+|-------|---------|--------|--------|-------|--------|
+| Unity | 0.3.x   | 0.4.x  | 0.5.x  | 1.x.x | 2.x.x  |
+| VNX   | 6.x.x   | 7.x.x  | 8.x.x  | 9.x.x | 10.x.x |
+
 License
 -------