yum install -y http://vortex-rpm.org/el5/noarch/vortex-release-5-1.vortex.el5.noarch.rpm
yum install -y http://vortex-rpm.org/el6/noarch/vortex-release-6-1.vortex.el6.noarch.rpm
yum install -y http://vortex-rpm.org/el7/noarch/vortex-release-7-2.vortex.el7.centos.noarch.rpm
Warning, EL5 trees are considered legacy and are not updating. Currently we build only for x86_64, support for i386 (probably) coming soon.