correct variable references to prevent incorrect globbing

setup.sh

@@ -67,7 +67,7 @@ done
 # using certbot?
 while true; do
     read -p "Are you using Certbot to handle your SSL certificates? (default: NO) " yn
-    case $yn in
+    case "${yn}" in
         [Yy]*)
             useCertbot=1
             break
@@ -91,7 +91,7 @@ done
 if [ "${useCertbot}" -eq 1 ]; then
     while true; do
         read -p "What is the primary domain for your Certbot Certificates? " inputCertbotDomain
-        case $inputCertbotDomain in
+        case "${inputCertbotDomain}" in
             '')
                 echo -e "\n${err}You cannot have an empty domain name${norm}"
                 ;;