ruby-on-rails - 如何升级rails？

Question

请帮助升级 rails 。现在我有 3.2.21 版。但我需要安装版本 4。

我尝试添加 Gemfile:

gem 'rails', '4.2.1'

并执行:

bundle install

但我收到以下错误信息:

sergey@sergey-H61M-D2-B3 ~/rails/project1 $ bundle install
Fetching gem metadata from https://rubygems.org/...........
Fetching gem metadata from https://rubygems.org/..
Resolving dependencies...
Bundler could not find compatible versions for gem "activesupport":
  In snapshot (Gemfile.lock):
    activesupport (3.2.21)

  In Gemfile:
    rails (= 4.2.1) ruby depends on
      activesupport (= 4.2.1) ruby

Running `bundle update` will rebuild your snapshot from scratch, using only
the gems in your Gemfile, which may resolve the conflict.

附言:

sergey@sergey-H61M-D2-B3 ~/rails/project1 $ bundle update
Fetching gem metadata from https://rubygems.org/...........
Fetching gem metadata from https://rubygems.org/..
Resolving dependencies...
Bundler could not find compatible versions for gem "railties":
  In Gemfile:
    coffee-rails (~> 3.2.1) ruby depends on
      railties (~> 3.2.0.beta) ruby

    rails (= 4.2.1) ruby depends on
      railties (4.2.1)

Answer 1

运行

bundle update

然后，做

bundle install

它应该修复。