Add more descriptive description

swagger2.cabal

@@ -1,7 +1,11 @@
 name:                swagger2
 version:             2.1.4.1
 synopsis:            Swagger 2.0 data model
-description:         Please see README.md
+description:
+  This library is inteded to be used for decoding and encoding Swagger 2.0 API
+  specifications as well as manipulating them.
+  .
+  The original Swagger 2.0 specification is available at http://swagger.io/specification/.
 homepage:            https://github.com/GetShopTV/swagger2
 bug-reports:         https://github.com/GetShopTV/swagger2/issues
 license:             BSD3