title: Strapi relations, returning other fields except id
body: <p>I want to make some simple Rest API backend with Strapi.io and I have no experience in backend, ORM, relations and etc., so I have troubles. Idea is make structure of dishes with ingridients and calculation. I have table ingridients, table compositions that have two fields ingridient id and amount of it. Also I have dishes table which belongs to many compositions. Right now I have this situation when I call api/dishes/3 and it's not suitable for me: </p>
  
  <pre><code>{
  "id": 3,
  "name": "DishName",
  "compositions": [
      {
          "id": 1,
          "amount": 100,
          "ingridient": 2,
          "dish": 3
      },
      {
          "id": 2,
          "amount": 100,
          "ingridient": 1,
          "dish": 3
      }
  ]}
  </code></pre>
  
  <p>I want API which work like this:</p>
  
  <pre><code>{
      "id": 3,
      "name": "DishName",
      "compositions": [
          {
              "id": 1,
              "amount": 100,
              "ingridient": { id: 1, name: "IngridientName" },
              "dish": 3
          },
          {
              "id": 2,
              "amount": 100,
              "ingridient": { id: 2, name: "SecondIngridientName" },
              "dish": 3
          }
      ]}
  </code></pre>