Update ruby gems.
Update ruby gems.

Spring 1.6.2 fixed the issue of https://github.com/rails/spring/issues/456

rubycentral/cfp-app,jsis/cfp.jsconf.is,rubycentral/cfp-app,rubycentral/cfp-app,jsis/cfp.jsconf.is,jsis/cfp.jsconf.is,ruby-no-kai/cfp-app,ruby-no-kai/cfp-app,ruby-no-kai/cfp-app