我正在Rails5上使用mysql2gem。如果有帮助的话，我还使用aws cloud9ec2示例进行开发。
我得到一个错误：

$ RAILS_ENV=development bundle exec rake db:setup 

rake aborted! 
Mysql2::Error::ConnectionError: 
Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' (2)

这是我的database.yml文件：

development:
  adapter: mysql2
  socket: /var/mysql/mysql.sock
  database: wagn_development
  username: user
  password: user
  host: localhost

test:
  adapter: mysql2
  socket: /var/mysql/mysql.sock
  database: wagn_test
  username: user
  password: user
  host: localhost

production:
  adapter: mysql2
  socket: /var/mysql/mysql.sock
  database: wagn_production
  username: user
  password: user
  host: localhost

如何解决错误？