anchor.diff:      pool.OpenAcademyCourse().AddCharField("Name", models.StringFieldParams{})
       pool.OpenAcademyCourse().AddTextField("Description", models.StringFieldParams{})
       pool.OpenAcademyCourse().AddMany2OneField("Responsible", models.ForeignKeyFieldParams{
  -        Relation: "User", OnDelete: models.SetNull, Index: true})
  +        RelationModel: pool.User(), OnDelete: models.SetNull, Index: true})
       pool.OpenAcademyCourse().AddOne2ManyField("Sessions", models.ReverseFieldParams{
  -        Relation: "OpenAcademySession", ReverseFK: "Course"})
  +        RelationModel: pool.OpenAcademySession(), ReverseFK: "Course"})
   }
   ----
   
  
positive.code: 
  [source,go]
  ----
  pool.SaleOrder().AddMany2OneField("Customer", models.ForeignKeyFieldParams{Relation: "Partner"})
  
  fmt.Println(myOrder().Customer().Name())
  ----
  
negative.code: duration and a number of seats. Although we could have used the same file
  we will create a new file for sessions to organise our code.
  
  NOTE: Don't forget to run `hexya generate` and `hexya updatedb` after creating
  the new model
  
  .openacademy/session.go
  [source,go]
  