title: angular-cli: Configure sass-loader to include node_modules in includePath
body: <p>angular-cli: 1.0.0-beta.15</p>
  
  <p>node: 6.5.0</p>
  
  <p>os: linux x64</p>
  
  <p>I want to compile the scss file from <code>bootstrap-material-design</code> v4-dev branch by putting it in the apps[0].styles[] array of <code>angular-cli.json</code>  but I get the following error:</p>
  
  <pre><code>ERROR in ./~/css-loader!./~/postcss-loader!./~/sass-loader!./~/bootstrap-material-design/scss/bootstrap-material-design.scss                                               
  Module build failed:                                                                                                                                                       
  @import "bootstrap/scss/variables"; // from bootstrap node_module                                                                                                          
  ^                                                                                                                                                                          
        File to import not found or unreadable: bootstrap/scss/variables                                                                                                     
  Parent style sheet: /home/ciesielskico/Documents/Git/reports/node_modules/bootstrap-material-design/scss/_variables.scss                
        in /home/ciesielskico/Documents/Git/reports/node_modules/bootstrap-material-design/scss/_variables.scss (line 45, column 1)       
   @ ./~/bootstrap-material-design/scss/bootstrap-material-design.scss 4:14-148                                                                                              
   @ multi styles
  </code></pre>
  
  <p>angular-cli.json</p>
  
  <pre><code>"styles": [
                  "../node_modules/bootstrap/scss/bootstrap-flex.scss",
                  "../node_modules/bootstrap-material-design/scss/bootstrap-material-design.scss",
  ]
  </code></pre>
  
  <p>On bootstrap-material-design's documentation it says to put node_modules in the includePath of the sass-loader.</p>
  
  <p>Is it possible with the current version of angular-cli?
  If yes, how?</p>