This project is to illustrate some weird duplications that can happen when using ‘joins`. These duplications happen when you do a join without selecting something from the joined association. When this happens rails execute a query similar to
“‘ SELECT parents.* FROM parents INNER JOIN children ON children.parent_id = parents.id “`
This will return duplicated ‘parents` rows and rails has no extra information on how to group them while instantiating the `Parent` objects
run the ‘test/unit/parent_test.rb` tests and look at the SQL for details and some ways to work around this issue