title: Slick DBIO sequence failing to compile
body: <p>I am trying to save model <code>ProductCategory</code> object in database. While saving it,<code>categoriesId</code> is a <code>Seq</code>.</p>
  
  <pre class="lang-scala prettyprint-override"><code>case class ProductCategory(productItemId: ProductItemId, categoryies: CategoryId, filterName: FilterName)
  
  /*Inside another object starts*/
  def saveCategoriesId(productItemId: ProductItemId, categoryId: Seq[CategoryId], filterName: FilterName):
        Future[Seq[ProductItemId]] =
          db.run({
            DBIO.sequence(categoryId.map(id =&gt; save(ProductCategory(productItemId, id, filterName))))
          })
  
  def save(productCategory: ProductCategory): DBIO[ProductItemId] = 
        query returning query.map(_.productItemId) += productCategory
  
  </code></pre>
  
  <p>Getting following error:</p>
  
  <pre><code>[error] /Users/vish/Work/jd/app/service/ProductCategoryService.scala:20:35: type mismatch;
  [error]  found   : Seq[slick.dbio.DBIOAction[models.ProductItemId,slick.dbio.NoStream,Nothing]]
  [error]  required: Seq[slick.dbio.DBIOAction[models.ProductItemId,slick.dbio.NoStream,E]]
  [error]       DBIO.sequence(categoryId.map(id =&gt; save(ProductCategory(productItemId, id, filterName))))
  </code></pre>
  
  <p>Playframework version is 2.6. This question is not duplicate of <a href="https://stackoverflow.com/questions/40758492/slick-combine-actions-with-a-seq-of-dbioaction">this</a>.This issue has blocked the further development. While answering please comment if it correct way of saving <code>categoriesId</code></p>