title: Bundler could not find compatible versions for gem "rack":
body: <p>I am new to Ruby but actually I don't need it if I don't want to install Redmine. I am following the instructions at <a href="http://www.redmine.org/projects/redmine/wiki/HowTo_install_Redmine_on_CentOS_Detailed" rel="nofollow">http://www.redmine.org/projects/redmine/wiki/HowTo_install_Redmine_on_CentOS_Detailed</a></p>
  
  <p>I have installed ruby 1.9 using </p>
  
  <pre><code>rvm install 1.9.3
  </code></pre>
  
  <p>and ruby gems using...</p>
  
  <pre><code>sudo yum install rubygems
  </code></pre>
  
  <p>Then coming to the part of creating the Gemfile and register these gems in it</p>
  
  <pre><code># file: /var/www/redmine/Gemfile
  source "http://rubygems.org" 
  gem "rake", "0.8.3" 
  gem "rack", "1.1.0" 
  gem "i18n", "0.4.2" 
  gem "rubytree", "0.5.2", :require =&gt; "tree" 
  gem "RedCloth", "~&gt;4.2.3", :require =&gt; "redcloth" # for CodeRay
  gem "mysql" 
  gem "coderay", "~&gt;0.9.7" 
  </code></pre>
  
  <p>and my file looks like...</p>
  
  <pre><code>source 'https://rubygems.org'
  gem "rake", "0.8.3"
  gem "rack", "1.1.0"
  gem "i18n", "0.4.2"
  gem "rubytree", "0.5.2", :require =&gt; "tree"
  gem "RedCloth", "~&gt;4.2.3", :require =&gt; "redcloth" # for CodeRay
  gem "mysql"
  
  
  gem "rails", "3.2.15"
  gem "jquery-rails", "~&gt; 2.0.2"
  gem "coderay", "~&gt; 1.1.0"
  gem "fastercsv", "~&gt; 1.5.0", :platforms =&gt; [:mri_18, :mingw_18, :jruby]
  gem "builder", "3.0.0"
  
  # Optional gem for LDAP authentication
  </code></pre>
  
  <p>When I run </p>
  
  <pre><code>bundle install
  </code></pre>
  
  <p>it gives me...</p>
  
  <pre><code>Please configure your config/database.yml first
  Fetching gem metadata from https://rubygems.org/.......
  Fetching additional metadata from https://rubygems.org/..
  Resolving dependencies...
  Bundler could not find compatible versions for gem "rack":
    In Gemfile:
      rails (= 3.2.15) ruby depends on
        rack (~&gt; 1.4.5) ruby
  
      rack (1.1.0)
  </code></pre>
  
  <p>I don't know what to do.</p>