我在使用 rails 连接到 mysql 数据库时遇到问题。我是 Rails 的新手，但我已经尝试过这里的指南：
OSX上的rails + MySQL：未加载库：libmysqlclient.18.dylib
这仍然行不通。我相信我安装了两个 mysql 安装，这让我很困惑。
我安装了 MAMP 和它自己的 mysql，我还安装了 rails mysql2 gem。当我按照上面提供的链接中的步骤进行操作时，我认为这是使用 MAMP mysql 安装而不是使用 rails gems 安装的 mysql2，因此它无法识别它。
有什么办法可以将两个mysql合并为一个吗？或者更容易修改rails以便它可以看到mysql2 gem？
这是我的错误：
~/Sites/RoR3-Essentials/simple_cms ->rails s
=> 启动 WEBrick
=> Rails 3.2.13 应用程序开始开发http://localhost:3000
=> 使用 -d 调用以分离
=> Ctrl-C 关闭服务器
退出
/Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `connect': 未知数据库 'simple_cms_development' (Mysql2::错误）
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `initialize'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `new'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `mysql2_connection'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout'
from /Users/markmilly/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection'
from /Users/markmilly/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:101:in `connection'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/railtie.rb:88:in `block in <class:Railtie>'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `instance_exec'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `run'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/initializable.rb:55:in `block in run_initializers'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `each'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `run_initializers'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/application.rb:136:in `initialize!'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /Users/markmilly/Sites/RoR3-Essentials/simple_cms/config/environment.rb:5:in `<top (required)>'
from /Users/markmilly/Sites/RoR3-Essentials/simple_cms/config.ru:3:in `require'
from /Users/markmilly/Sites/RoR3-Essentials/simple_cms/config.ru:3:in `block in <main>'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
from /Users/markmilly/Sites/RoR3-Essentials/simple_cms/config.ru:in `new'
from /Users/markmilly/Sites/RoR3-Essentials/simple_cms/config.ru:in `<main>'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands/server.rb:46:in `app'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands/server.rb:70:in `start'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands.rb:55:in `block in <top (required)>'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
from /Users/markmilly/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'