ubutun下rails连接mysql数据库问题

本人初学Rails，发现在ubuntu下连接mysql必须指定mysql.sock才能成功,现把我的配置文件贴出来

# MySQL (default setup).  Versions 4.1 and 5.0 are recommended.
#
# Install the MySQL driver:
#   gem install mysql
# On MacOS X:
#   gem install mysql -- --include=/usr/local/lib
# On Windows:
#   gem install mysql
#       Choose the win32 build.
#       Install MySQL and put its /bin directory on your path.
#
# And be sure to use new-style password hashing:
#   http://dev.mysql.com/doc/refman/5.0/en/old-client.html
development:
  adapter: mysql
  database: todo_development
  username:
  password:
  host: localhost
  socket: /var/run/mysqld/mysqld.sock

# Warning: The database defined as 'test' will be erased and
# re-generated from your development database when you run 'rake'.
# Do not set this db to the same as development or production.
test:
  adapter: mysql
  database: todo_test
  username:
  password:
  host: localhost
  socket: /var/run/mysqld/mysqld.sock

production:
  adapter: mysql
  database: todo_production
  username:
  password:
  host: localhost
  socket: /var/run/mysqld/mysqld.sock
以上配置文件我已经试过，其他的方法还有，需要大家去试！