title: Why I am getting NoExplicitTypeError?
body: <p>I am createing <code>Nest.js</code> application and I decided to create my project with GrapQL. I read some documentation and I decided to go <strong>code first</strong> approach(GraphQL schema should automagically render itself). For this approach it was needed to install <strong>type-graphql</strong> which is really cool, but after I created some simple examples with only primary types I decided to do something more challanging. </p>
  
  <p>In my appliaction I have <code>BlogEntity</code>(from those <strong>Entities</strong> type-graphql is generating GraphQL schema) which is using <code>ArticleEntity</code> becouse it is needed to add typing to <code>posts</code>, <code>projects</code> and <code>tutorials</code>. I created my resolver and defined <code>@ResolveProperty</code> for <code>posts</code>, <code>projects</code> and <code>tutorials</code>. When I am trying to run <code>nest start</code> command i am getting this error:</p>
  
  <blockquote>
    <p>throw new errors_1.NoExplicitTypeError(prototype.constructor.name, propertyKey, parameterIndex);</p>
    
    <blockquote>
      <p>NoExplicitTypeError: You need to provide explicit type for BlogEntity#posts !</p>
    </blockquote>
  </blockquote>
  
  <p>Can someone explain me why I am getting this error and what should I do to fix it?</p>
  
  <p><strong>BlogEntity</strong></p>
  
  <pre class="lang-js prettyprint-override"><code>import { Entity, Column, ObjectIdColumn } from 'typeorm';
  import { Field, ID, ObjectType } from 'type-graphql';
  import { ArticleEntity } from '../../articles/models/article.entity';
  
  @Entity()
  @ObjectType()
  export class BlogEntity {
    @Field(() =&gt; ID)
    @ObjectIdColumn()
    _id: string;
  
    @Field()
    @Column()
    posts: ArticleEntity[];
  
    @Field()
    @Column()
    projects: ArticleEntity[];
  
    @Field()
    @Column()
    tutorials: ArticleEntity[];
  }
  </code></pre>
  
  <p><strong>BlogResolver</strong></p>
  
  <pre class="lang-js prettyprint-override"><code>@Resolver(() =&gt; BlogEntity)
  export class BlogResolver {
    constructor(
      private readonly blogService: BlogService,
      private readonly articlesService: ArticlesService) {}
  
    @Query(() =&gt; String)
    async helloBlog(): Promise&lt;string&gt; {
      return 'Hello blog';
    }
  
    @ResolveProperty('posts', () =&gt; ArticleEntity)
    async getPosts(): Promise&lt;ArticleEntity[]&gt; {
      return await this.articlesService.findAll();
    }
  
    @ResolveProperty('projects', () =&gt; ArticleEntity)
    async getProjects(): Promise&lt;ArticleEntity[]&gt; {
      return await this.articlesService.findAll();
    }
  
    @ResolveProperty('tutorials', () =&gt; ArticleEntity)
    async getTutorials(): Promise&lt;ArticleEntity[]&gt; {
      return await this.articlesService.findAll();
    }
  
  }
  </code></pre>
  
  <p>If you need anything else ping me in the comment section</p>