Update
Now that I’ve karma wh..err mined enough from this answer everyone should know that this should have been fixed.
re: via Ownatik again bundle install fails with SSL certificate verification error
gem update --system
My answer is still correct and left below for reference if that ends up not working for you.
Honestly the best temporary solution is to
[…] use the non-ssl version of rubygems in your gemfile as a temporary workaround.
via user Ownatik
what they mean is at the top of the Gemfile
in your rails application directory change
source 'https://rubygems.org'
to
source 'http://rubygems.org'
note that the second version is http instead of https