I've been struggling with this for a few hours. Everything just stopped working and I can't get it to work anymore. I'm a noob at Ruby, Ruby on Rails and the Terminal in general. This is really frustrating me so I just try to describe my problem as detailed as possible hoping someone can give me a solution.

I'm on Mac OS X Snow Leopard. I couldn't get Rails working at all just now: Could not find gem 'rails' headaches

But after some tries of reinstalling it, it suddenly worked again. But now I just can't get MySQL to work, and it sometimes even breaks the Rails installation again.

This is what I do:

sudo gem uninstall rails
sudo gem uninstall mysql
sudo gem uninstall mysql2

After these commands, I check the installed gems with gem list. No MySQL gem is listed anymore, but I can still see rails (2.3.5, 2.2.2, 1.2.6) . Is this normal? Does this mean I have 3 Rails installations? It doesn't make sense to me. Anyway, then I do this:

sudo gem clean

Which fails completely. I get a bunch of errors like this:

Attempting to uninstall fcgi-0.8.7
Unable to uninstall fcgi-0.8.7:
Gem::InstallError: cannot uninstall, check gem list -d fcgi

It doesn't uninstall anything. At this point, I try to install everything again. I start with:

sudo gem install rails

Which succeeds (I think):

Successfully installed rails-3.0.3
Successfully installed builder-2.1.2
2 gems installed
Installing ri documentation for rails-3.0.3...
File not found: lib

Then, I update RubyGems:

sudo gem update --system
sudo gem install rubygems-update
sudo update_rubygems

Then it says I have 1.3.7 installed, so it succeeded, I think. So now I proceed with installing MySQL. I already got MySQL 5.5.8 installed on my machine. I did some research about installing MySQL on Snow Leopard, and it seems I have to use this command:

sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config

I get a bunch of errors like this:

No definition for time_set_neg
No definition for time_set_second_part
No definition for time_equal
No definition for error_errno

At this point, I assume I got both Rails and the MySQL gem installed, so I try to start a new project.

rails new user_group -d mysql

It works! Rails is installed correctly. Now, I try generating a model.

cd user_group
rails generate model User

It fails with this error:

Could not find gem 'mysql2 (>= 0, runtime)' in any of the gem sources listed in your Gemfile.
Try running bundle install.

So I try running bundle install. It installs a lot of gems. Then I try to generate my model again. I get this error:

Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle: dlopen(/Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle, 9): Library not loaded: libmysqlclient.16.dylib (LoadError)
Referenced from: /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle
Reason: image not found - /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle

This is as far as I can get. What should I do? And why should this be so hard...