错误信息如下:
/home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in require': /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/2.1.0/x86_64-linux/digest/md5.so: undefined symbol: rb_Digest_MD5_Init - /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/2.1.0/x86_64-linux/digest/md5.so (LoadError)
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in
require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.0.4/lib/rails/generators/app_base.rb:1:in <top (required)>'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in
require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.0.4/lib/rails/generators/rails/app/app_generator.rb:1:in
'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in
require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.0.4/lib/rails/commands/application.rb:29:in <top (required)>'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in
require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.0.4/lib/rails/cli.rb:15:in
'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:45:in
require'
from /home/zengfb/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.0.4/bin/rails:9:in <top (required)>'
from /home/zengfb/.rbenv/versions/2.1.0/bin/rails:23:in
load'
from /home/zengfb/.rbenv/versions/2.1.0/bin/rails:23:in `