update readme with ontology diagram

Author: kschweikert

FIO - FIO V2.png

@@ -3,4 +3,7 @@
 The Facilities and Industries Ontology represents facilities and their industry classification. It is extended by the us_frs ontology that incorporates facilities from EPA facility registry service, and the naics and sic ontologies that implement the industry classification schemes. 
 
 ## Schema Diagram
-https://lucid.app/lucidchart/0b649dc4-e466-4d29-ae34-5c0f113f5a46/edit?viewport_loc=-1453%2C-27%2C2951%2C1455%2Cq4u-GszAWYkJ&invitationId=inv_0e3483a0-96fc-4faf-8c17-1a5bf73fd23b 
+[FIO ontology schema diagram](https://lucid.app/lucidchart/0b649dc4-e466-4d29-ae34-5c0f113f5a46/edit?viewport_loc=-1453%2C-27%2C2951%2C1455%2Cq4u-GszAWYkJ&invitationId=inv_0e3483a0-96fc-4faf-8c17-1a5bf73fd23b)
+
+Overview 
+![FIO schema diagram](./FIO%20-%20FIO%20V2.png)