title: How to use RelatedSel() method on beego framework properly
body: <p>I know this is very basic, but i think the official documentation at [beego website][1]</p>
  
  <p>[1]: <a href="http://beego.me/docs/mvc/model/query.md" rel="nofollow">http://beego.me/docs/mvc/model/query.md</a> doesn't give clear direction.</p>
  
  <p>I made a RESTful API using beego framework. As it promised, it generates basic CRUD code for my app. The problem is READ method doesn't return all data. By all data  I mean data in a table including data from all tables related to it. </p>
  
  <p>this is the output from the generated code (i'm using swagger to call it):</p>
  
  <pre><code>{
    "data": [
      {
        "Id": 1,
        "CustomerId": {
          "Id": 2,
          "Name": "",
          "Phone": "",
          "Email": "",
          "CreatedAt": "0001-01-01T00:00:00Z",
          "UpdatedAt": "0001-01-01T00:00:00Z"
        },
        "Saldo": 2500000,
        "CreatedAt": "2014-12-10T08:10:10+07:00",
        "UpdatedAt": "2014-12-10T08:10:10+07:00"
      }
    ],
    "totals": 1
  }
  </code></pre>
  
  <p>see, it doesn't return the Name, Phone, and Email.
  so i look into documentation and found this method RelatedSel() but still I have no idea how to use it properly.</p>
  
  <p>here's my code:</p>
  
  <pre><code>func GetAllCustomerSaldo(query map[string]string, fields []string, sortby []string, order []string,
      offset int64, limit int64) (ml []interface{}, err error, totals int64) {
      o := orm.NewOrm()
      qs := o.QueryTable(new(CustomerSaldo))
      qs.RelatedSel("CustomerId__Customers").All(&amp;CustomerSaldo{})
  ...
  </code></pre>
  
  <p>after trying many parameter possibilities, i still get this error:</p>
  
  <pre><code>Handler crashed with error unknown model/table name `Customers`
  </code></pre>
  
  <p>Anyone here have same problem with me? any solution guys?</p>