Add URL for the generated documentation, update building instructions

README.txt

-``zodbdocs`` contains all ZODB relevant documentation like "ZODB/ZEO
-Programming Guide", some ZODB articles and links to the ZODB release notes.
+==================
+ZODB documentation
+==================
+
+``zodbdocs`` is the source documentation for the website http://zodb.org. It
+contains all ZODB relevant documentation like "ZODB/ZEO Programming Guide",
+some ZODB articles and links to the ZODB release notes.
+
+
+Building the documentation
+--------------------------
+
 All documentation is formatted as restructured text. To generate HTML using
-Sphinx simply type "make html".
+Sphinx, use the following::
+
+    python bootstrap.py
+    ./bin/buildout
+    make html