Download the cacert. Pem </ code> file
http://download.csdn.net/download/u011534057/9847571
Create folder,C:\RailsInstaller
Save to
C:\RailsInstaller\cacert.pem
.
Type in the command line CMD or Ruby prompt, and jekyll s will be fine
set SSL_CERT_FILE=C:\RailsInstaller\cacert.pem