title: AngularCLI and Angular Material (schematics) error: Collection "@angular/material" cannot be resolved
body: <p>I am trying to use the Angular schemats that are shown on <a href="https://material.angular.io/guide/schematics" rel="noreferrer">this page.</a>
  When I try to use this following command in the terminal at the root of the project <strong>ng generate @angular/material:material-nav --name name-of-new-nav</strong>, I get the following error in red,</p>
  
  <blockquote>
    <p>Collection "@angular/material" cannot be resolved. Error: Collection
    "@angular/material" cannot be resolved.
        at NodeModulesEngineHost._resolveCollectionPath (/Users/jeremypeters/MEGA/development/learning/angular/material-learn/node_modules/@angular-devkit/schematics/tools/node-module-engine-host.js:88:15)
        at NodeModulesEngineHost.createCollectionDescription (/Users/jeremypeters/MEGA/development/learning/angular/material-learn/node_modules/@angular-devkit/schematics/tools/file-system-engine-host-base.js:106:27)
        at SchematicEngine._createCollectionDescription (/Users/jeremypeters/MEGA/development/learning/angular/material-learn/node_modules/@angular-devkit/schematics/src/engine/engine.js:78:40)
        at SchematicEngine.createCollection (/Users/jeremypeters/MEGA/development/learning/angular/material-learn/node_modules/@angular-devkit/schematics/src/engine/engine.js:71:43)
        at Object.getCollection (/Users/jeremypeters/MEGA/development/learning/angular/material-learn/node_modules/@angular/cli/utilities/schematics.js:28:31)
        at GenerateCommand.getOptions (/Users/jeremypeters/MEGA/development/learning/angular/material-learn/node_modules/@angular/cli/models/schematic-command.js:193:41)
        at GenerateCommand. (/Users/jeremypeters/MEGA/development/learning/angular/material-learn/node_modules/@angular/cli/commands/generate.js:38:53)
        at Generator.next ()
        at /Users/jeremypeters/MEGA/development/learning/angular/material-learn/node_modules/@angular/cli/commands/generate.js:7:71
        at new Promise ()</p>
  </blockquote>
  
  <p>How do I get this to work?</p>
  
  <p>Info: Angular CLI: 6.0.8</p>