Update README.md

Added Extending and integrating section

Author: bufke

README.md

@@ -39,7 +39,7 @@ REPORT_BUILDER_EXCLUDE = ['user'] # Allow all models except User to be accessed
 Export to Report action is disabled by default. To enable set
 REPORT_BUILDER_GLOBAL_EXPORT = True
 
-# Django-SIS Usage
+# Django-SIS Example
 
 Django-SIS is a good example integration of report_builder. Note we've given report_builder a grappelli theme by modifying
 templates.
@@ -96,9 +96,23 @@ Using the example above, consider the use case of a user wanting to pull the stu
 ![](https://raw.github.com/burke-software/django-report-builder/master/screenshots/reportfilterstab.png)
 
 
+# Extending and integrating django-report-builder
+## Format 
+Note many python format features require >= 2.7
+http://docs.python.org/2/library/string.html#string-formatting
 
+You may add formats in /admin/report_builder/format. See http://docs.python.org/2/library/string.html#format-examples
 
+There are also some examples included in the south migrations. If you use south django-report-builder comes with
+a few formats for you.
 
+## Integrations
+Give django-report-builder a native look and feel. django-sis shows a good example of a django-grappelli
+like style.
+
+https://github.com/burke-software/django-sis/tree/master/templates/report_builder
+
+Note I use django-apptemplates in this example to specify which app template I'm extending.