I ran this:

yum install wget git unzip
yum group install "Development Tools"
yum install epel-release
yum -y update
wget -P /tmp/ https://packages.erlang-solutions.com/erlang-solutions-1.0-1.noarch.rpm
sudo rpm -Uvh erlang-solutions-1.0-1.noarch.rpm
rpm -Uvh erlang-solutions-1.0-1.noarch.rpm
cd /tmp/
rpm -Uvh erlang-solutions-1.0-1.noarch.rpm
yum install erlang erlang-parsetools erlang-xmerl
wget -P /tmp/ https://github.com/elixir-lang/elixir/releases/download/v1.8.1/Precompiled.zip
mkdir -p /opt/elixir
unzip /tmp/Precompiled.zip -d /opt/elixir
for e in elixir elixirc iex mix; do sudo ln -s /opt/elixir/bin/${e} /usr/local/bin/${e}; done
yum install https://download.postgresql.org/pub/repos/yum/11/redhat/rhel-7-x86_64/pgdg-centos11-11-2.noarch.rpm
yum install postgresql11-server postgresql11-contrib
/usr/pgsql-11/bin/postgresql-11-setup initdb
vim /var/lib/pgsql/11/data/pg_hba.conf 
systemctl enable --now postgresql-11.service
useradd -r -s /bin/false -m -d /var/lib/pleroma -U pleroma
mkdir -p /opt/pleroma
chown -R pleroma:pleroma /opt/pleroma
su -l pleroma -s $SHELL -c 'git clone https://git.pleroma.social/pleroma/pleroma /opt/pleroma'
su -l pleroma -s $SHELL -c 'git clone https://git.pleroma.social/pleroma/pleroma.git /opt/pleroma'
cd /opt/pleroma
su -l pleroma -s $SHELL -c 'cd /opt/pleroma/ && mix deps.get'
su -l pleroma -s $SHELL -c 'cd /opt/pleroma/ && mix pleroma.instance gen'
vim config/generated_config.exs 
mv config/generated_config.exs config/prod.secret.exs
su -l postgres -s $SHELL -c 'cd /opt/pleroma/ && psql -f config/setup_db.psql'
su -l pleroma -s $SHELL -c 'cd /opt/pleroma/ && MIX_ENV=prod mix ecto.migrate'
yum install certbot-nginx
mkdir -p /var/lib/letsencrypt/
systemctl stop nginx
certbot certonly --email mark+pleroma@fingers.today -d pleroma.fingers.today --standalone
cp /opt/pleroma/installation/pleroma.nginx /etc/nginx/conf.d/pleroma.fingers.today.conf
vim /etc/nginx/conf.d/pleroma.fingers.today.conf
systemctl start nginx
cp /opt/pleroma/installation/pleroma.service /etc/systemd/system/pleroma.service
vim /etc/systemd/system/pleroma.service 
systemctl enable --now pleroma.service