[FLOW3-general] How to create association ?

[Dawid Pacholczyk]

Hello,
  I`m tring to use association OneToOne so I wrote

@OneToOne(targetEntity="Second")

but I can`t pass validation. The example above is from Doctrine 
documentation. Why can`t I use that ? How should I create connection 
beetwen two entities ?

Best regards,
Dawid Pacholczyk