当我尝试使用 rails generate mongoid:config 时出现以下错误找不到生成器 mongoid:config。如果我指定 gem 'mongoid'、'3.1.4'，它会给我以下信息：
Bundler 找不到 gem "activemodel" 的兼容版本：在 Gemfile 中：mongoid (= 3.1.4) x86-mingw32 依赖于 activemodel (~> 3.2) x86-mingw32
rails (= 4.0.0.rc2) x86-mingw32 depends on activemodel (4.0.0.rc2)
请帮忙。谢谢！
GemFile: gem 'rails', '4.0.0.rc2'
gem 'mongoid'
gem 'mongoid-paperclip'
gem 'bson_ext'
GemFile.lock
GEM
specs:
actionmailer (4.0.0.rc2)
actionpack (= 4.0.0.rc2)
mail (~> 2.5.3)
actionpack (4.0.0.rc2)
activesupport (= 4.0.0.rc2)
builder (~> 3.1.0)
erubis (~> 2.7.0)
rack (~> 1.5.2)
rack-test (~> 0.6.2)
activemodel (4.0.0.rc2)
activesupport (= 4.0.0.rc2)
builder (~> 3.1.0)
activerecord (4.0.0.rc2)
activemodel (= 4.0.0.rc2)
activerecord-deprecated_finders (~> 1.0.2)
activesupport (= 4.0.0.rc2)
arel (~> 4.0.0)
activerecord-deprecated_finders (1.0.3)
activesupport (4.0.0.rc2)
i18n (~> 0.6, >= 0.6.4)
minitest (~> 4.2)
multi_json (~> 1.3)
thread_safe (~> 0.1)
tzinfo (~> 0.3.37)
arel (4.0.0)
atomic (1.1.9)
bson (1.9.0)
bson_ext (1.9.0)
bson (~> 1.9.0)
builder (3.1.4)
climate_control (0.0.3)
activesupport (>= 3.0)
cocaine (0.5.1)
climate_control (>= 0.0.3, < 1.0)
coffee-rails (4.0.0)
coffee-script (>= 2.2.0)
railties (>= 4.0.0.beta, < 5.0)
coffee-script (2.2.0)
coffee-script-source
execjs
coffee-script-source (1.6.2)
durran-validatable (2.0.1)
erubis (2.7.0)
execjs (1.4.0)
multi_json (~> 1.0)
hike (1.2.3)
i18n (0.6.4)
jbuilder (1.4.2)
activesupport (>= 3.0.0)
multi_json (>= 1.2.0)
jquery-rails (3.0.1)
railties (>= 3.0, < 5.0)
thor (>= 0.14, < 2.0)
json (1.8.0)
leshill-will_paginate (2.3.11)
mail (2.5.4)
mime-types (~> 1.16)
treetop (~> 1.4.8)
mime-types (1.23)
minitest (4.7.4)
mongo (1.9.0)
bson (~> 1.9.0)
mongoid (1.0.6)
activesupport (>= 2.2.2)
durran-validatable (>= 2.0.1)
leshill-will_paginate (>= 2.3.11)
mongo (>= 0.18.2)
mongoid-paperclip (0.0.8)
paperclip (>= 2.3.6)
multi_json (1.7.7)
paperclip (3.4.2)
activemodel (>= 3.0.0)
activerecord (>= 3.0.0)
activesupport (>= 3.0.0)
cocaine (~> 0.5.0)
mime-types
polyglot (0.3.3)
rack (1.5.2)
rack-test (0.6.2)
rack (>= 1.0)
rails (4.0.0.rc2)
actionmailer (= 4.0.0.rc2)
actionpack (= 4.0.0.rc2)
activerecord (= 4.0.0.rc2)
activesupport (= 4.0.0.rc2)
bundler (>= 1.3.0, < 2.0)
railties (= 4.0.0.rc2)
sprockets-rails (~> 2.0.0)
railties (4.0.0.rc2)
actionpack (= 4.0.0.rc2)
activesupport (= 4.0.0.rc2)
rake (>= 0.8.7)
thor (>= 0.18.1, < 2.0)
rake (10.0.4)
rdoc (3.12.2)
json (~> 1.4)
sass (3.2.9)
sass-rails (4.0.0.rc2)
railties (>= 4.0.0.beta, < 5.0)
sass (>= 3.1.10)
sprockets-rails (~> 2.0.0)
sdoc (0.3.20)
json (>= 1.1.3)
rdoc (~> 3.10)
sprockets (2.10.0)
hike (~> 1.2)
multi_json (~> 1.0)
rack (~> 1.0)
tilt (~> 1.1, != 1.3.0)
sprockets-rails (2.0.0)
actionpack (>= 3.0)
activesupport (>= 3.0)
sprockets (~> 2.8)
thor (0.18.1)
thread_safe (0.1.0)
atomic
tilt (1.4.1)
treetop (1.4.14)
polyglot
polyglot (>= 0.3.1)
turbolinks (1.2.0)
coffee-rails
tzinfo (0.3.37)
uglifier (2.1.1)
execjs (>= 0.3.0)
multi_json (~> 1.0, >= 1.0.2)
PLATFORMS
x86-mingw32
DEPENDENCIES
bson_ext
coffee-rails (~> 4.0.0)
jbuilder (~> 1.2)
jquery-rails
mongoid
mongoid-paperclip
rails (= 4.0.0.rc2)
sass-rails (~> 4.0.0.rc2)
sdoc
turbolinks
uglifier (>= 1.3.0)