Update PMObjectContext.m

Author: vilanovi

Source/PMObjectContext.m

@@ -324,6 +324,7 @@ - (PMBaseObject*)pmd_baseObjectFromModelObject:(id<PMPersistentObject>)modelObje
     NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
 
     PMBaseObject *baseObject = [unarchiver decodeObject];
+    baseObject.key = modelObject.key;
     [baseObject registerToContext:self];
     baseObject.lastUpdate = modelObject.lastUpdate;