[FEATURE] improve scss-lint installation

core/installers/ruby.sh

 #!/bin/bash
 
-echo -e "\033[0;34mInstall scss-lint\033[0m";
-sudo gem install scss_lint
+if [ ! -z `which nvm` > /dev/null ]
+then
+	echo -e "\033[0;34mInstall scss-lint\033[0m";
+	if [ $OSTYPE == "msys" ]
+	then
+		gem install scss_lint
+	else
+		sudo gem install scss_lint
+	fi
+else
+	echo -e "\n\033[0;31mYou need to have ruby installed on your machine in order for scss-lint to work!\033[0m\n";
+fi
+