Add doc links in readme

Add additional documentation links in README.md.

Signed-off-by: Zhikui Ren <zhikui.ren@intel.com>
Change-Id: If74c819a09e2b7de061737be15fcb7fcc49fccd6
diff --git a/README.md b/README.md
index a1b9244..b5065ba 100644
--- a/README.md
+++ b/README.md
@@ -122,3 +122,8 @@
 entity-manager to produce a Redfish compliant REST API.
 **intel-ipmi-oem** An implementation of the IPMI SDR, FRU, and Storage commands
 that utilize Entity Manager as the source of information.
+
+## Additional Documentation
+1. **[Entity Manager DBus API](https://github.com/openbmc/entity-manager/blob/master/docs/EntityManagerDbusAPI.md)**
+2. **[My First Sensor Example](https://github.com/openbmc/entity-manager/blob/master/docs/my_first_sensors.md)**
+3. **[Configuration File Schema](https://github.com/openbmc/entity-manager/tree/master/schemas)**
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