logs for a certain block, change the log level for that block.

*   ActiveSupport::BufferedLogger#open_log is deprecated.  This method should
    not have been public in the first place.

*   ActiveSupport::BufferedLogger's behavior of automatically creating the
    directory for your log file is deprecated.  Please make sure to create the
    directory for your log file before instantiating.

*   ActiveSupport::BufferedLogger#auto_flushing is deprecated.  Either set the
    sync level on the underlying file handle like this:

        f = File.open('foo.log', 'w')
        f.sync = true
        ActiveSupport::BufferedLogger.new f

    Or tune your filesystem.  The FS cache is now what controls flushing.

*   ActiveSupport::BufferedLogger#flush is deprecated.  Set sync on your
    filehandle, or tune your filesystem.