title: Nest dependency resolution issue with tsconfig paths and barrel files/same directory imports
body: <p>I've set a few different paths in tsconfig.json to make importing of controllers, entities, services, etc. easier to deal with.  Relevant portion of tsconfig.json:</p>
  
  <pre><code>...
  "baseUrl": "./src",
  "paths": {
    "@hello/controllers": [
      "./controllers"
    ],
    "@hello/entities": [
      "./entity"
    ],
    "@hello/services": [
      "./services"
    ]
  },
  ...
  </code></pre>
  
  <p>I've also created barrel files (index.ts) within the src/controllers/, src/entity/, and src/services/ directories that re-exports all of the classes that I need from within those directories.</p>
  
  <p>Everything works as expected when importing a service from a file that is within my controllers directory. Example:</p>
  
  <pre><code>// src/controllers/comment.controller.ts
  // This works
  import { CommentService } from '@hello/services';
  
  @Controller()
  export class CommentController {...}
  </code></pre>
  
  <p>Things do <strong>NOT</strong> work when importing a service from another service file that is within the <strong>same</strong> directory. Example</p>
  
  <pre><code>// src/services/comment.service.ts
  // This does NOT work
  import { StoryService, UserService } from '@hello/services';
  // StoryService, UserService, and CommentService are in the src/services directory 
  
  @Injectable()
  export class CommentService {...}
  </code></pre>
  
  <p>The error that I get when doing the above is:</p>
  
  <pre><code>Error: Nest can't resolve dependencies of the CommentService (?, +). Please make sure that the argument at index [0] is available in the AppModule context.
  </code></pre>
  
  <p><strong>Expected behavior</strong>
  I expect dependencies to resolve using a path defined in tsconfig.json, even if they're being imported from within the same directory.</p>
  
  <p><strong>Possible Solution</strong>
  My current workaround is to import the files using relative paths:</p>
  
  <pre><code>// src/services/comment.service.ts
  // This does work
  import { StoryService } from './story.service';
  import { UserService } from './user.service';
  // I'd prefer to do this:
  // import { StoryService, UserService } from '@hello/services';
  
  @Injectable()
  export class CommentService {...}
  </code></pre>
  
  <p><strong>Environment</strong>
  @nestjs/common@5.7.4
  @nestjs/core@5.7.4
  typescript@3.6.2</p>
  
  <p><strong>Update</strong>
  My index.ts barrel file in src/services is shown below:</p>
  
  <pre><code>// src/services/index.ts
  export * from './comment.service';
  export * from './story.service';
  export * from './user.service';
  </code></pre>