Here are the places I have already tried to find the answer: tutorials point, stackoverflow, another stack overflow, and the official guide.
I still have no idea what I am doing wrong. After I have configured the database.yml correctly, I try to create the project and this is the error I get:
"Please update your PATH to include build tools or download the DevKit from 'http://rubyinstaller.org/downloads' and follow the instructions at 'http://github.com/oneclick/rubyinstaller/wiki/Development-Kit'
An error occurred while installing mysql2 (0.3.13), and Bundler cannot continue.
Make sure that gem install mysql2 -v '0.3.13' succeeds before bundling."
Why can't I find mysql2 v0.3.13?
OS: Windows 7 Rails: 4.0.0 Ruby: 1.9.3 DevKit installed
Errors that I have encountered
$ bundle exec rails s
Could not locate Gemfile
$ bundle
Bundler::GemfileNotFound
`$ gem install mysql2
Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...
ERROR:  Error installing mysql2:
        ERROR: Failed to build gem native extension.
        c:/Ruby193/bin/ruby.exe extconf.rb
checking for rb_thread_blocking_region()... yes
checking for rb_wait_for_single_fd()... yes
checking for rb_hash_dup()... yes
checking for rb_intern3()... yes
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.
Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=c:/Ruby193/bin/ruby
        --with-mysql-dir
        --without-mysql-dir
        --with-mysql-include
        --without-mysql-include=${mysql-dir}/include
        --with-mysql-lib
        --without-mysql-lib=${mysql-dir}/lib
extconf.rb:37:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError)
Gem files will remain installed in c:/Ruby193/lib/ruby/gems/1.9.1/gems/mysql2-0.3.13 for inspection.`
 
     
    