rails 数据库配置
驱动配置：Gemfile:gem 'mysql2', '0.2.6' 或者gem install mysql2 --with-mysql-dir=/usr/local/mysql --with-mysql-config=/usr/local/mysql/bin/mysql_configwindows 两者均可，linux推荐第二种，给驱动指定部分参数（根据你mysql数据库的安装）
database.yml配置development: adapter: mysql2 encoding: utf8 reconnect: false database: xxx pool: 5 username: xxx password: xxx host: xxx.xxx.x.xxx
