In RedHat derived distributions, you can use the official Crystal repository.
First you have to add the repository to your YUM configuration. For easy setup just run in your command line:
curl https://dist.crystal-lang.org/rpm/setup.sh | sudo bash
That will add the signing key and the repository configuration. If you prefer to do it manually execute:
rpm --import https://dist.crystal-lang.org/rpm/RPM-GPG-KEY
cat > /etc/yum.repos.d/crystal.repo <<END
[crystal]
name = Crystal
baseurl = https://dist.crystal-lang.org/rpm/
END
Once the repository is configured you're ready to install Crystal:
sudo yum install crystal
When a new Crystal version is released you can upgrade your system using:
sudo yum update crystal