I recently scaffolded a new webapp with Yeoman (1.4.5). In my Gruntfile.js I have set the following config:

```
...

// Compiles Sass to CSS and generates necessary files if requested
sass: {
  options: {
    lineNumbers:true,
    sourceMap: true,
    includePaths: ['bower_components']
  }
...

```

Even though Grunt (grunt-cli v0.1.13) handles my instructions without errors and everything is running smoothly, unfortunately no SASS line numbers are showing up in my compiled CSS files? 
Am I missing something or is this an issue with the grunt-sass node package? I would like to keep my automated task instructions centralized in my gruntfile.js. Any help would be greatly appreciated!