[RefResolver]: updated docs on ref resolving to local files

docs/references.rst

@@ -2,6 +2,34 @@
 Resolving JSON References
 =========================
 
+How to use the RefResolver
+--------------------------
+
+This section is intended for those who are having problems with using $ref to
+load other schemas from within a given schema.
+
+Loading schemas from within the filesystem requires setting a base uri for
+the RefResolver. Otherwise, finding another schema relative to a first schema
+will not work.
+
+.. code-block:: python
+
+        import os
+        from jsonschema import Draft4Validator, RefResolver
+
+        def get_draft4_validator(schema_absolute_path):
+          """
+          Return a draft4 validator with the base_uri
+          set to the schema path so that file refs are resolved
+          """
+          with open(schema_absolute_path) as schema_file:
+            schema = json.load(schema_file)
+          resolver = RefResolver("file://" + schema_absolute_path, schema)
+          return Draft4Validator(schema, resolver=resolver)
+
+
+
+
 
 .. currentmodule:: jsonschema