Revised ERD readme file

- updated Editing Recommendation
- Udate Documentation instructions

docbook/erd/README

@@ -16,9 +16,10 @@ Editing Recommendations
 * Position the tables to minimize the number of intersections between the
   relationships lines (not always easy as the software does not offer much
   flexibility for positioning the connectors).
-* Prior to saving the file, update the MantisBT and Schema version numbers in
-  the 'Title' note (top-left corner); particularly, do not forget to bump the
-  revision number.
+* Update the MantisBT and Schema version numbers as appropriate in the
+  'Title' note (top-left corner) of the diagram
+* Do not forget to bump the revision number
+* Save the file
 
 
 Exporting
@@ -40,3 +41,21 @@ where
   * SSS is the corresponding schema version (e.g. 183)
   * R indicates the diagram's revision number
   * XXX is the file's extension (e.g. pdf, png)
+
+
+Updating the Documentation
+--------------------------
+
+To keep the Developers Guide up-to-date as the ERD is modified:
+
+1. Export the diagram as PNG
+2. Save the file in /docbook/Developers_Guide/en-US/images/erd.png
+3. Build the docbook and check that the updated file is there
+4. Commit changes
+
+Also remember to update the PDF on http://mantisbt.org/docs/erd
+
+1. Export the diagram as single-file PDF
+2. Save the file to a temp location as per above naming convention
+3. Upload the file to the server
+4. Remove the old file if necessary