title: 'ng add @angular/material' produces error, why?
body: <p>When I try to install angular material components by using the <code>ng add</code> command I get an <code>package already installed</code> error.</p>
  <blockquote>
  <p>$ ng add @angular/material<br />
  Skipping installation: Package already installed</p>
  <p>Cannot find module '@angular-devkit/schematics/tasks'<br />
  Error: Cannot find module '@angular-devkit/schematics/tasks'<br />
  at Function.Module._resolveFilename (internal/modules/cjs/loader.js:580:15)<br />
  at Function.Module._load (internal/modules/cjs/loader.js:506:25)<br />
  at Module.require (internal/modules/cjs/loader.js:636:17)<br />
  at require (internal/modules/cjs/helpers.js:20:18)<br />
  at Object.  (C:\Users\emilbonnek\node_modules@angular\material\schematics\ng-add\index.js:10:17)<br />
  at Module._compile (internal/modules/cjs/loader.js:688:30)<br />
  at Object.Module._extensions..js (internal/modules/cjs/loader.js:699:10)<br />
  at Module.load (internal/modules/cjs/loader.js:598:32)<br />
  at tryModuleLoad (internal/modules/cjs/loader.js:537:12)<br />
  at Function.Module._load (internal/modules/cjs/loader.js:529:3)<br />
  at Module.require (internal/modules/cjs/loader.js:636:17)<br />
  at require (internal/modules/cjs/helpers.js:20:18)<br />
  at new ExportStringRef(C:\Users\emilbonnek\Documents\private\ultimating\node_modules@angular-devkit\schematics\tools\export-ref.js:18:25)<br />
  at NodeModulesEngineHost._resolveReferenceString
  (C:\Users\emilbonnek\Documents\private\ultimating\node_modules@angular-devkit\schematics\tools\node-module-engine-host.js:94:21)<br />
  at NodeModulesEngineHost.createSchematicDescription(C:\Users\emilbonnek\Documents\private\ultimating\node_modules@angular-devkit\schematics\tools\file-system-engine-host-base.js:179:34)<br />
  at SchematicEngine.createSchematic (C:\Users\emilbonnek\Documents\private\ultimating\node_modules@angular-devkit\schematics\src\engine\engine.js:219:38)</p>
  </blockquote>
  <p>I don't have access to any of the modules, so I don't think its because the package is already installed, however it could be that I have simply misunderstood something about schematics.</p>
  <p>I am on angular CLI version 8.0.3 and same for devkit/core and devkit/schematics. I am completely sure I am running the command in the right directory.</p>
  <p>Why is the command not doing as it is supposed to? any help is appreciated.</p>