Link preserves-schema to main page

README.md

@@ -18,11 +18,17 @@ comparable to JSON, XML, S-expressions, CBOR, ASN.1 BER, and so on.
 
 ## Core documents
 
+### Preserves data model and serialization formats
+
  - [Preserves tutorial](TUTORIAL.html)
  - [Preserves specification](preserves.html), including semantics,
    textual syntax, and compact binary syntax
  - [Canonical Form for Binary Syntax](canonical-binary.html)
 
+### Preserves schema
+
+ - [Preserves Schema specification](preserves-schema.html)
+
 ## Additional resources
 
  - Some [conventions for common data types](conventions.html)