title: TypeORM one-to-many relation using Entity Schema
body: <p>I have two entities Projects &amp; Orders. I want to have One-to-Many Orders in Projects and Many-to-One project in Orders.</p>
  <p>Many-to-one side is working fine.</p>
  <p>When I try to add One-to-Many in Project entity and try to fetch all, I get following error:</p>
  <pre><code>&quot;Cannot read property 'joinColumns' of undefined&quot;
  </code></pre>
  <p><strong>Project Entity</strong></p>
  <pre><code>const { EntitySchema } = require('typeorm');
  const { BaseRelations, BaseColumns } = require('../BaseEntity');
  
  module.exports = new EntitySchema({
    name: 'Project',    
    columns: {
      ...BaseColumns,
      name: {
        type: 'varchar',
      }
    },
    relations: {
      ...BaseRelations,
      orders: {
        type: 'one-to-many',
        target: 'Order',
        cascade: true,
      },
    },
  });
  </code></pre>
  <p><strong>Order Entity</strong></p>
  <pre><code>const { EntitySchema } = require('typeorm');
  
  module.exports = new EntitySchema({
    name: 'Order',
    columns: {
      id: {
        primary: true,
        type: 'int',
        generated: true,
      },
      name: {
        type: 'varchar',
        name: 'name',
      },
    },
    relations: {
      project: {
        type: 'many-to-one',
        target: 'Project',
        joinColumn: {
          name: 'project_id',
        },
      }
    },
  });
  </code></pre>