added ruby install script

backend/scripts/install-ruby.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+apt-get update
+apt-get install -y curl
+
+curl -sSL https://get.rvm.io | bash -s stable
+source /etc/profile.d/rvm.sh
+
+echo `rvm list known`
+rvm install 2.6.1
+
+echo `ruby -v`