title: Relative module was not found in Vue.js when build project
body: <p>I have a project on Vue.js with Typescript and when I run dev server (prod build too) it returns error in console:</p>
  
  <blockquote>
    <p>ERROR  Failed to compile with 1 errors<br>
     This relative module was not found:</p>
    
    <p>*./app.vue in ./src/main.ts</p>
  </blockquote>
  
  <p>I alredy tried to checkout previous project commits, update global and local packages, clone and build project on other machines, delete and reinstall packages, delete package-lock.json, create new project via vue cli and add project files on new configuration - and nothing was changed. Same error. Very strange for me.</p>
  
  <p>Here is my main.ts</p>
  
  <pre><code>import Vue from 'vue';
  import App from './app.vue';
  import router from './router';
  import store from './store';
  
  Vue.config.productionTip = false;
  
  new Vue({
    router,
    store,
    render: (h) =&gt; h(App)
  }).$mount('#app');
  </code></pre>
  
  <p>And here App.vue</p>
  
  <pre><code>&lt;template&gt;
    &lt;div id="app" class="container-fluid"&gt;
      &lt;header-component&gt;&lt;/header-component&gt;
      &lt;main id="content" class="content row"&gt;
        &lt;transition name="fade"&gt;
          &lt;router-view/&gt;
        &lt;/transition&gt;
      &lt;/main&gt;
      &lt;footer-component&gt;&lt;/footer-component&gt;
    &lt;/div&gt;
  &lt;/template&gt;
  
  &lt;script lang="ts"&gt;
  import { Component, Vue } from 'vue-property-decorator';
  import HeaderComponent from './components/header/header.component';
  import FooterComponent from './components/footer/footer.component';
  
  @Component({
    components: {
      HeaderComponent,
      FooterComponent
    }
  })
  export default class App extends Vue {}
  &lt;/script&gt;
  
  &lt;style lang="scss"&gt;
  @import "../node_modules/bootstrap/dist/css/bootstrap.min.css";
  @import "../node_modules/font-awesome/css/font-awesome.min.css";
  @import "../node_modules/vue2-animate/dist/vue2-animate.min.css";
  @import "./styles/main.scss";
  &lt;/style&gt;
  </code></pre>
  
  <p>Thanks in advance for help.</p>