Config class writes out its values

Config.py

@@ -1,6 +1,14 @@
 
 class Config:
     def __init__(self, filename):
+        self.filename = filename
+        self.vars = {}
         if os.path.isfile(filename):
             f = open(filename, 'r')
-            eval(f, self)
+            eval(f, self.vars)
+
+    def write(self):
+        f = open(self.filename, 'w')
+        for var in self.vars:
+            f.write("%s = %s\n" % (var, repr(self.vars[var])))
+        f.close()