Переопределить переменные начальной загрузки в twitter-bootstrap-rails gem

Как использовать пользовательские переменные при использовании драгоценного камня twitter-bootstrap-rails? Я хочу изменить ширину сетки по умолчанию и добавил следующую строку в свой файл bootstrap_and_overrides, но ничего не происходит...

@gridColumnWidth: 50px;

Что я делаю неправильно?

Вот мой файл bootstrap_and_overrides:

  3 @import "twitter/bootstrap/bootstrap";
  4 body { padding-top: 60px; }
  5     
  6 @import "twitter/bootstrap/responsive";
  7     
  8 // Set the correct sprite paths
  9 @iconSpritePath: asset-path('twitter/bootstrap/glyphicons-halflings.png');
 10 @iconWhiteSpritePath: asset-path('twitter/bootstrap/glyphicons-halflings-white.png');
 11     
 12 // Set the Font Awesome (Font Awesome is default. You can disable by commenting below lines)
 13 @fontAwesomeEotPath: asset-path('fontawesome-webfont.eot');
 14 @fontAwesomeWoffPath: asset-path('fontawesome-webfont.woff');
 15 @fontAwesomeTtfPath: asset-path('fontawesome-webfont.ttf');
 16 @fontAwesomeSvgzPath: asset-path('fontawesome-webfont.svgz');
 17 @fontAwesomeSvgPath: asset-path('fontawesome-webfont.svg');
 18 
 19 // Font Awesome
 20 @import "fontawesome";
 21 
 22 // Your custom LESS stylesheets goes here
 23 //
 24 // Since bootstrap was imported above you have access to its mixins which
 25 // you may use and inherit here
 26 //
 27 // If you'd like to override bootstrap's own variables, you can do so here as well
 28 // See http://twitter.github.com/bootstrap/less.html for their names and documentation
 29 //  
 30 // Example:
 31 // @linkColor: #ff0000;    
 32 
 33 // -----------------------------------------------------
 34     
 35 @gridColumnWidth: 50px;

Вот мой файл applicaiton.css:

  1 /*
  2  * This is a manifest file that'll be compiled into application.css, which will include all the files
  3  * listed below.           
  4  *
  5  * Any CSS and SCSS file within this directory, lib/assets/stylesheets, vendor/assets/stylesheets,
  6  * or vendor/assets/stylesheets of plugins, if any, can be referenced here using a relative path.
  7  *
  8  * You're free to add application-wide styles to this file and they'll appear at the top of the
  9  * compiled file, but it's generally better to create a new file per style scope.
 10  *
 11  *= require_self
 12  *= require_tree .         
 13  *= require bootstrap_and_overrides
 14 */  
 15     
 16     
 17 .my_background_plate {     
 18   background-color: #eee;
 19   border: 1px #ddd solid;
 20   -moz-border-radius: 5px; 
 21   border-radius: 5px;
 22   padding: 15px;
 23   margin-bottom: 15px;
 24   margin-top: 15px;        
 25 }
 26 
 27 .my_crud_btn {             
 28   margin-top: 5px;         
 29   margin-left: 15px;       
 30 }
 31 
 32 #footer {                  
 33   margin: 15px 0;          
 34   background-color: black; 
 35 }