added simple objects relationships model to the design documentation
diff --git a/docs/design/design-3.html b/docs/design/design-3.html
index bc57b17..e1b07d3 100644
--- a/docs/design/design-3.html
+++ b/docs/design/design-3.html
@@ -280,7 +280,7 @@
their relationships</p>
<center>
- <image alt="to be added">
+ <img src="simple-model.png" width=453 height=378>
</center>
<p>Note that this picture will be updated at the end of the next
diff --git a/docs/design/simple-model.png b/docs/design/simple-model.png
new file mode 100644
index 0000000..2543404
Binary files /dev/null and b/docs/design/simple-model.png differ