```ruby
dir 'core_gems'
download "bundler", "1.7.13"
download "json", "1.8.2"
download "msgpack", "0.5.11"
download "cool.io", "1.3.0"
download "http_parser.rb", "0.6.0"
download "yajl-ruby", "1.2.1"
download "sigdump", "0.2.2"
download "thread_safe", "0.3.5"
download "tzinfo", "1.2.2"
download "tzinfo-data", "1.2015.2"
```

Update core gems. sigdump and tzinfo-data
user
```ruby
dir 'core_gems'
download "bundler", "1.7.13"
download "json", "1.8.2"
download "msgpack", "0.5.11"
download "cool.io", "1.3.0"
download "http_parser.rb", "0.6.0"
download "yajl-ruby", "1.2.1"
download "sigdump", "0.2.3"
download "thread_safe", "0.3.5"
download "tzinfo", "1.2.2"
download "tzinfo-data", "1.2015.4"
```
assistant