1. console 
    sudo apt-get install mysql-server mysql-client libmysqlclient-dev
  2. gemfile 
    gem 'mysql2', '~> 0.5.2'
  3. database.yml
default: &default
  adapter: mysql2
  encoding: utf8
  pool: 5
  username: root
  password: root
  socket: /var/run/mysqld/mysqld.sock

development:
  <<: *default
  database: projectname_development

test:
  <<: *default
  database: projectname_test

production:
  <<: *default
  database: projectname_production
  username: projectname
  password: <%= ENV['PROJECTNAME_DATABASE_PASSWORD'] %>

note that above we set a password root - we need it to make it work correctly

  1. set mysql passwort to be root. source on stackoverflow

console

sudo mysql

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'root';

press Ctrl + D to exit

  1. that’s it! now you can run migrations

console

rails db:create
rails db:migrate
  1. Troubleshooting
# log in with user "root" and input password on next step
mysql -u root -p
# view all mysql users
SELECT user,authentication_string,plugin,host FROM mysql.user;

# start/stop/restart mysql
brew services start mysql
brew services stop mysql
brew services restart mysql

# find socket for connecting to mysql for database.yml
mysqladmin variables | grep socket

# socket: /var/run/mysqld/mysqld.sock
# socket: /tmp/mysqld.sock
socket: /tmp/mysql.sock