Updated documentation about the network class

HACKING

@@ -98,6 +98,12 @@ doesn't support some functionality (e.g. reposts), simply don't
 declare the function. :class:`NetworkBase` offers good defaults to
 all functions (basically, returning nothing.)
 
+class Connection
+----------------
+Inside your module, you should have at least once class called
+``Connection``. As pointed before, it should inherit from the
+:class:`NetworkBase` clas.
+
 Base Return Object
 ------------------
 Most functions will return a :class:`NetworkData` object. It offers