Ubuntu 16.04 部署出错

BigNerdCoding — Sat, 18 Mar 2017 23:31:51 +0800

initialize': Cannot assign requested address - bind(2) for "IP"

(Backtrace restricted to imported tasks)
cap aborted!
Don't know how to build task 'start' (see --tasks)

请各位大师给解答一下疑问

Rails 中 Model 的属性验证出错 undefined local variable or method

BigNerdCoding — Mon, 12 Dec 2016 22:09:26 +0800

最近开始学 Rails，买了安道的书。在做练习的时候出现了一个很奇怪的问题：

class User < ApplicationRecord
    validates name, presence: true
    validates email, presence: true
end

加上 email 的验证会出现如下图所示错误，百思不解。希望能够得到解答