CLC-4091 - Create script to obtain and serve a cached set of Canvas section enrollments

https://jira.ets.berkeley.edu/jira/browse/CLC-4091
Just wanted to remind you that CSV Row objects are not instances of Hash but do implement the ['key'] method, so this test might end up being unpleasantly brittle someday. It's probably best *not* to check for specific classes unless we really, really depend on untested aspects of the class being there.