redminelib/resources: add eq metamethod

To test whether, for example, a project looked up earlier is equal to
the project associated with an issue or tracker.

Signed-off-by: Patrick Donnelly <batrick@batbytes.com>

redminelib/resources/base.py

@@ -172,6 +172,12 @@ def __init__(self, manager, attributes):
         if self._relations_name is None:
             self._relations_name = self.__class__.__name__.lower()
 
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return self.internal_id == other.internal_id
+        else:
+            return False
+
     def __getitem__(self, item):
         """
         Provides dictionary-like access to Resource attributes.