Add a yum repo manually by adding a configuration file in /etc/yum.repo.d/ directory.

<pre lang="bash">cd /etc/yum.repos.d/
vi newrepo

Add the following.

<pre lang="bash">[newrepo]
name=New Repo for RHEL/ CentOS $releasever - $basearch
baseurl=http://newrepo.domain.com/centos/$releasever/$basearch/
enabled=1
gpgcheck=1
gpgkey=http://newrepo.domain.com/RPM-GPG-KEY.txt

You may need to import the key.

<pre lang="bash">rpm --import http://newrepo.domain.com/RPM-GPG-KEY.txt

Finally, test the new repo by running the following.

<pre lang="bash">yum update -y
yum install new-package