In some databases (e.g, mysql) column names referenced in ORDER BY clauses
should be quoted in case they contain reserved words. This corrects an issue that
occurs when using the Model.order(:symbol) method if :symbol happens to be a reserved
word (e.g., "key").
Most AR methods handle this correctly, so calling Model.where(:key) would not fail
but Model.order(:key) would.
This problem was originally reported as issue #2601.