Flush from the seeInRepository method

Hello. First of all, thank you for the great testing framework.
I would like to clarify how to use the `seeInRepository` method. I have read the documentation and can't understand why this method executes the doctrine's flush. I had a few cases when I had forgotten to add the flush in the app and had got green tests because of this behavior. Maybe the flush from this method is not a good idea?

The issue names the seeInRepository method but no files or tests. Start by locating that method in the module and checking its existing test coverage and documentation; done requires a decided flush behavior, matching tests, and documentation that explains the result.

索引モデルが issue の本文から書いたものです。