Reload the runner if structure.sql changes

[Earlopain]

Closes #326

There already exists a test that modifications to structure.sql ends up reloading but without proper integration tests this behaviour isn't really testable.

To confirm this works:

• Get a rails app with structure.sql
• Make a change and save, look at the log output to validate it reloaded.
• Make some changes to a *.rb file to confirm that this new listener doesn't overwrite the main one.

[andyw8]

Thank you! I've tested and it's working well.

[andyw8]

Let's also update workspace_did_change_watched_files to remove structure.sql? We can add a comment that it's only for Ruby files. Ignore, misunderstood.

[vinistock]

Just needs a rebase, but LGTM.