def create
    @task = current_user.tasks.build(task_params)
    @task.complete = false

     n=1
      loop do
        unless Task.find_by priority: n
          @task.priority=n
          break
        end
        n+=1
      end

    respond_to do |format|
    if @task.save
      format.html { redirect_to user_tasks_path(current_user) }
      format.js
    else
      format.html { render action: 'new' }
      format.js
    end
   end
  end

class Task < ActiveRecord::Base

 def priority_increment
     n=1
      loop do
        unless Task.find_by priority: n
          @task.priority=n
          break
        end
        n+=1
      end
  end
end

class Task < ActiveRecord::Base

 def priority_increment
     n=1
      loop do
        unless Task.find_by priority: n
          self.priority=n
          break
        end
        n+=1
      end
  end
end

@task.priority_increment