アップデートした El Capitan で Library not loaded: libmysqlclient.18.dylib (LoadError) と出る

Yosemite から El Capitan にアップデートしたら、rails sをしたら、

bin/rails:6: warning: already initialized constant APP_PATH
***/bin/rails:6: warning: previous
definition of APP_PATH was here Usage: rails COMMAND [ARGS]

The most common rails commands are:  generate    Generate new code
(short-cut alias: "g")  console     Start the Rails console (short-cut
alias: "c")  server      Start the Rails server (short-cut alias: "s")
dbconsole   Start a console for the database specified in
config/database.yml
             (short-cut alias: "db")  new         Create a new Rails application. "rails new my_app" creates a
             new application called MyApp in "./my_app"

In addition to those, there are:  application  Generate the Rails
application code  destroy      Undo code generated with "generate"
(short-cut alias: "d")  plugin new   Generates skeleton for developing
a Rails plugin  runner       Run a piece of code in the application
environment (short-cut alias: "r")

All commands can be run with -h (or --help) for more information.

と出るようになってしまいました。

rake rails:update:bin を打つと、情報が出てくるということで（http://ja.stackoverflow.com/questions/10290/warning-already-initialized-constant-app-path）打ってみたところ、
Library not loaded: libmysqlclient.18.dylib (LoadError) と出てしまいました。。。

どうやら、 libmysqlclient.18.dylib　が見つからない模様。

Yosemite までは、 sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib とやるといいらしいんですが、例によってできないので、

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

Relative path not allowed in OS X: "unsafe use of relative rpath libmysqlclient.18.dylib" · Issue #646 · brianmario/mysql2

El Capitanだとこれが有効なようです。
これで、Library not loaded: libmysqlclient.18.dylib (LoadError) は出なくなりました。