解决redis集群安装问题:ruby依赖redis.gem /usr/local/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require': cannot load such file -- redis (LoadError) from /usr/local/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require' from ./redis-trib.rb:25:in `'