Since polyamorous 1.1.0 [differs from 1.2.0](activerecord-hackery/polyamorous@ca95023) only by the version number and the README file, it's perfectly unacquired to simply change the dependency version.

Copied from [5bf84bd](activerecord-hackery/squeel@5bf84b) which is not on the master branch, so can't be referenced.

…rphic joins erros in squeel (activerecord-hackery#369 and activerecord-hackery#380).

ruby 2.4 deprecated Fixnum and Bignum, replacing them with a single
unified Integer class.

Fix 'NoMethodError: undefined method `last_comment'' errors when trying
to run rake for this gem. Rake 11.0.1 removes the last_comment method
which rspec-core (< 3.4.4) uses. Therefore until/if a patch is released
we need to pin rake to an older version in Gemfile:

  gem 'rake', '< 11.0'

Then:

  bundle exec rake install

https://stackoverflow.com/questions/35893584/nomethoderror-undefined-method-last-comment-after-upgrading-to-rake-11