Add extrinsic record

extrinsic_record.json

@@ -0,0 +1,4 @@
+{
+  "extrinsic": "7515801-21",
+  "hotkey": "5GRF9pN3wqjG24ep54BdU19zLcfyN8f289o8eGXrAmsmwKz5"
+}