def authenticate = Action { implicit request =>
        signinForm.bindFromRequest.fold(
          formWithErrors => BadRequest(html.signin(formWithErrors)),
          user => Redirect(routes.Application.active).withSession(Security.username -> User.getUserName(user))
        )
      }

def authenticate(email: String, password: String) : Option[User] = {
    (findByEmail(email)).filter { (user => BCrypt.checkpw(password, user.password)) }
  }

  def findByEmail(email: String) : Option[User] = {
    UserDAO.findOne(MongoDBObject("email" -> email))
  }

val signinForm = Form {
    mapping(
      "email" -> nonEmptyText,
      "password" -> text)(User.authenticate)(_.map(user => (user.email, "")))
      .verifying("Invalid email or password", result => result.isDefined)
  }

  def authenticate = Action { implicit request =>
    signinForm.bindFromRequest.fold(
      formWithErrors => BadRequest(html.signin(formWithErrors)),
      user => Redirect(routes.Application.active).withSession(Security.username -> User.getUserName(user.get))
    )
  }

val optUser: Option[User] = ...
val user: User = optUser.get

val optUser: Option[User] = ...
optUser match {
  case Some(user) => // do something with user
  case None => // do something to handle the absent user
}

val optUser: Option[User] = ...
optUser.map(user => doSomething(user))