Add Interface definition yaml file for LED Manager

This adds the interface definition file for LED manager daemon that deals with
LED groups. Currently, this daemon wants only a dbus property which can be
altered by the user to assert/de-assert the group

Fixes openbmc/openbmc#736

Change-Id: Ib554d7dfd8d6addf7064eeeadaa25e91d32aaf5a
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/xyz/openbmc_project/Led/Group.interface.yaml b/xyz/openbmc_project/Led/Group.interface.yaml
new file mode 100644
index 0000000..121fe80
--- /dev/null
+++ b/xyz/openbmc_project/Led/Group.interface.yaml
@@ -0,0 +1,8 @@
+description: >
+    Interface to control LED groups.
+properties:
+    - name: Asserted
+      type: boolean
+      description: >
+        Whether or not the group is currently asserted.
+        To assert a group, set to True. To de-assert a group, set to False.