Change whole MySQL database collation to utf8mb4 with LHM

change_collation_db_wide.rb

class ChangeCollationDbWide < ActiveRecord::Migration[5.2]
  def change
    db = ActiveRecord::Base.connection
    tables = ActiveRecord::Base.connection.tables.map { |t| t.to_sym }
    
    tables.each do |t|
      Lhm.change_table(t) do |table|
        table.ddl "ALTER TABLE `#{table.name}` DEFAULT CHARACTER SET utf8mb4, DEFAULT COLLATE utf8mb4_unicode_ci"
      end
    end
  end
end