prepend sudo on the adminstrative commands

doc/install.md

@@ -11,9 +11,9 @@ The current version of SOCTools only runs on a single server. A fully distribute
 
 * Minimal installation of CentOS7
 * Install Ansible
-  * `yum -y install epel-release`  
-  * `yum -y install ansible git`
-  * `ansible-galaxy collection install ansible.posix`
+  * `sudo yum -y install epel-release`  
+  * `sudo yum -y install ansible git`
+  * `sudo ansible-galaxy collection install ansible.posix`
 
 ## Clone SOCTools
 * `git clone https://gitlab.geant.org/gn4-3-wp8-t3.1-soc/soctools.git`