The mysql gem does not support ruby version 2.4 and is not actively developed now. Probably I should switch from the mysql gem to the mysql2 gem. For a while, please use older Ruby such as Ruby 2.3.3. I am sorry for any inconvenience this issue may cause.
misshie
commented
7 years ago
The mysql gem does not support ruby version 2.4 and is not actively developed now. Probably I should switch from the mysql gem to the mysql2 gem. For a while, please use older Ruby such as Ruby 2.3.3. I am sorry for any inconvenience this issue may cause.
See also: https://stackoverflow.com/questions/41520996/mysql-gem-install-error-on-ruby-2-4