我几天都在修补这个，我仍然得到同样的错误。对于初学者，我已经能够以sqlite作为数据库启动一个新的rails应用程序，但我们正在使用的应用程序使用Mysql。因此，当我转到app目录并输入“rails server”时，它会给我以下内容：
/Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/mysql2-0.2.7/lib/mysql2.rb:8:in `require': dlopen(/Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/mysql2-0.2.7/lib/mysql2/mysql2.bundle, 9): Library not loaded: libmysqlclient.18.dylib (LoadError)
Referenced from: /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/mysql2-0.2.7/lib/mysql2/mysql2.bundle
Reason: image not found - /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/mysql2-0.2.7/lib/mysql2/mysql2.bundle
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/mysql2-0.2.7/lib/mysql2.rb:8:in `<top (required)>'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/bundler-1.0.15/lib/bundler/runtime.rb:68:in `require'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/bundler-1.0.15/lib/bundler/runtime.rb:68:in `block (2 levels) in require'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/bundler-1.0.15/lib/bundler/runtime.rb:66:in `each'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/bundler-1.0.15/lib/bundler/runtime.rb:66:in `block in require'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/bundler-1.0.15/lib/bundler/runtime.rb:55:in `each'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/bundler-1.0.15/lib/bundler/runtime.rb:55:in `require'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/bundler-1.0.15/lib/bundler.rb:120:in `require'
from /Users/gojinjedi/Sites/bluey/config/application.rb:7:in `<top (required)>'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railties-3.0.7/lib/rails/commands.rb:28:in `require'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railties-3.0.7/lib/rails/commands.rb:28:in `block in <top (required)>'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railties-3.0.7/lib/rails/commands.rb:27:in `tap'
from /Users/gojinjedi/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railties-3.0.7/lib/rails/commands.rb:27:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
所以（我认为）没有安装MySQL开发头文件，我在网上搜索如何安装它们并尝试了大多数安装命令行还没有成功。我试过的命令示例：
gem install mysql2
sudo env ARCHFLAGS="-arch i386" gem install mysql -- --with-mysql-dir=/usr/local/mysql --with-mysql-lib=/usr/local/mysql/lib --with-mysql-include=/usr/local/mysql/include
我在app目录中完成了bundle install，bundle update和bundle命令......我的选项用完了......你能帮助我吗？
我在mac osx 10.7