A lot of Rails apps are using the gem
did_you_mean to help during development. Most of these apps are probably going to run into an issue when upgrading to Ruby 2.3, which pulled the gem into Ruby core.
A graceful method of upgrading Ruby is to update the Gemfile version of
0.10.0 if it wasn’t already. That version was released 4 months before Ruby 2.3, so some apps may already be using it. Version
0.10.0 works with both 2.3 and previous versions.
Fix came from this Github issue