Revert "Make id partitioning for string similar to integer"

This reverts commit 068022541786e8c06caa15f864cdd0ab0569b2f7.

This change broke one of our production applications due to the use of ~> in the Gemfile (all generated URLs became incorrect).

This pull request is submitted under the assumption that breaking changes should be reserved for major releases and its inclusion in a patch revision was a mistake.

Thanks