小编Zee*_*han的帖子

我正在使用以下版本的rails,ruby和mongoid创建一个测试应用程序.

rails 4 beta
ruby 2.0.0
mongoid 3.1.2

我GemFile看起来像这样

gem 'rails', '4.0.0.beta1'
ruby '2.0.0'
gem 'mongoid', '~> 3.1.2'
gem 'bson_ext'

但是,当我bundle在控制台上运行时,我得到以下错误.

Bundler找不到gem"activemodel"的兼容版本:

Fetching gem metadata from https://rubygems.org/...........
Fetching gem metadata from https://rubygems.org/..
Resolving dependencies...
Bundler could not find compatible versions for gem "activemodel":
  In Gemfile:
    mongoid (~> 3.1.2) ruby depends on
      activemodel (~> 3.2) ruby

    rails (= 4.0.0.beta1) ruby depends on
      activemodel (4.0.0.beta1)

有人可以帮忙吗？请.....