I have installed docker on centos 7. by running following commands,
curl -sSL https://get.docker.com/ | sh systemctl enable docker && systemctl start do
first of all please check if docker-compose is installed,
$ docker-compose -v
If it is not installed, please refer to the installation guide https://docs.docker.com/compose/install/ If installed give executable permission to the binary.
$ chmod +x /usr/local/bin/docker-compose
check if this works.