README.schema: add file naming conventions

Avoid arguments in peer review by adding a blurb that indicates the
desired file naming conventions for configuration and schema files.

Change-Id: I62ce2694ed6405b12ff2b7a69d246c90f399568a
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/schemas/README.schema b/schemas/README.schema
index 36e44f6..15bdf81 100644
--- a/schemas/README.schema
+++ b/schemas/README.schema
@@ -11,6 +11,10 @@
 in a single file, or can be organized into several smaller files.  Thus, the
 top most schema describes a single object or an array of objects.
 
+To remain consistent with the OpenBMC CPP source code file name guidelines,
+entity manager configuration file and schema file names must be
+lower_snake_case.
+
 A single entity manager configuration
 ----------------------------------------
 At its core entity manager simply exports objects onto DBus when a specific