add exception notification gem. close #248
fixed ruby 2.0.0 run zc error.
add pry-nav gem for quick debug.
add ruby-2.0.0 for travis-ci test.
upgrade rails to 3.2.12
merge.
Merge pull request #269 from saberma/saberma-bug/fixed-ruby-2.0-run-zc-error

修正 ruby 2.0.0 运行 zeus server 时的错误
Merge pull request #270 from saberma/saberma-enhancement/add-pry-nav-for-quick-debug

加入 pry-nav Gem，方便调试
Merge pull request #271 from saberma/saberma-enhancement/add-ruby-2.0-for-travis-ci-test

travis-ci 配置加入对 ruby-2.0.0 环境的测试
Merge pull request #272 from saberma/saberma-enhancement/upgrade-rails-3.2.12

升级 rails 版本到 3.2.12
remove unneccessary bootstrap css and js. close #275
minor change.
add cohort analysis. #close 268
remove therubyracer gem.
Merge pull request #278 from saberma/saberma-enhancement/remove-therubyracer-gem

去掉 therubyracer gem.
update deploy config.
add daemons gem for delayed job.
add nginx config template.
[deploy]fixed host missing.
serve /uploads