Implement each() convenience method

lib/nntp/tiny/db.py

@@ -43,6 +43,15 @@ class DatabaseTableCursor():
     def fetchall(self):
         return map(self.__map__, self.cr.fetchall())
 
+    def each(self):
+        while True:
+            obj = self.fetchone()
+
+            if obj is None:
+                break
+
+            yield obj
+
 class Database():
     __slots__ = 'db',