Rails 5.2 needs mysql2 version >= 0.4.4

[mihailpozarski]

When creating a new project with potassium using MySQL and Rails 5.2 there is a ActiveRecord dependency not met. Gem::LoadError: Error loading the 'mysql2' Active Record adapter. Missing a gem it depends on? can't activate mysql2 (< 0.6.0, >= 0.4.4), already activated mysql2-0.3.21. Make sure all dependencies are added to Gemfile.

Gemfile asks for:

#Gemfile
gem 'mysql2', '~> 0.3.18'

ActiveRecord requires mysql2 (< 0.6.0, >= 0.4.4) on rails version 5.2 asked at gemfile:

#Gemfile
gem 'rails', '~> 5.2.3'

As explained here:
RailsApps/rails_apps_composer#371