title: GORM findAll doesn't work
body: <p>A have class Product:</p>
  
  <pre><code>class Product {
      static hasMany = [attributeValues: ProductAttributeValue]
  
      String productId
      String manufacturer
      BigDecimal price
  
      static constraints = {
          productId unique: true, blank: false
          manufacturer blank: false
          price min: BigDecimal.ZERO
      }
  }
  </code></pre>
  
  <p>I want to find all products, which productId contains substring 'filter'.
  I wrote next code:</p>
  
  <pre><code>Product.findAll {it.productId.contains(filter)}
  </code></pre>
  
  <p>But it doesn't work. Why?</p>