Check if user input empty username

lib/menu.sh

@@ -176,7 +176,12 @@ install_site() {
         fi
     done
 
+    while true; do
     read -p "Enter admin username: " ADMIN_USER
+        if validate_username "$ADMIN_USER"; then
+            break
+        fi
+    done
 
     read -s -p "Enter password (press Enter for random password): " ADMIN_PASSWORD
     echo

lib/validation.sh

@@ -14,4 +14,12 @@ validate_email() {
         return 1
     fi
     return 0
+}
+
+validate_username() {
+    if [[ -z "$1" ]] || [[ "$1" =~ ^[[:space:]]*$ ]]; then
+        echo -e "${RED}Username cannot be empty${NC}"
+        return 1
+    fi
+    return 0
 }