Library not loaded: libmysqlclient.18.dylib (LoadError) on Mac OS

When installed raisl 4.0.1, it's raise some error:

/opt/local/lib/ruby2.0/gems/2.0.0/gems/mysql2-0.3.14/lib/mysql2.rb:8:in `require': dlopen(/opt/local/lib/ruby2.0/gems/2.0.0/extensions/x86_64-darwin-13/2.0.0/mysql2-0.3.14/mysql2/mysql2.bundle, 9): Library not loaded: libmysqlclient.18.dylib (LoadError)
  Referenced from: /opt/local/lib/ruby2.0/gems/2.0.0/extensions/x86_64-darwin-13/2.0.0/mysql2-0.3.14/mysql2/mysql2.bundle
  Reason: no suitable image found.  Did find

to fix this problem, type command below:

sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib