我已经成功安装了rails 4并使用rails 4.0.0创建了项目
rails s
第一次工作正常。但是在gemfile中添加了“ devise” gem之后
gem 'devise', '~> 3.0.0.rc'
并运行捆绑安装，出现以下错误。该错误的原因是什么，将如何解决？
我也尝试在gem'devise'部分添加注释，但是现在每个Rails命令都出现相同的错误。
/home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:205:in `parse': (<unknown>): mapping values are not allowed in this context at line 2 column 11 (Psych::SyntaxError)
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:205:in `parse_stream'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:153:in `parse'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:129:in `load'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/config_file.rb:318:in `load_file'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/config_file.rb:191:in `initialize'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/gem_runner.rb:66:in `new'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/gem_runner.rb:66:in `do_configuration'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/gem_runner.rb:46:in `run'
database.yml文件
development:
adapter: mysql2
encoding: utf8
database: realstate_development
pool: 5
username: root
password: root
socket: /var/run/mysqld/mysqld.sock
任何版本的gem'devise'都在捆绑软件上显示以下错误，如果我删除devise gem可以正常工作，我使用的是rails 3.2.13，但我从未遇到过这样的问题，这很奇怪。
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