fixed snake case conversion

src/Utils/Business/LuStringUtils.php

@@ -14,7 +14,7 @@ class LuStringUtils
 {
     public static function snakeToCamelCase($string, $capitalizeFirstCharacter)
     {
-        $str = preg_replace_callback("/_[a-zA-Z]/", function($matches)
+        $str = preg_replace_callback("/_[a-zA-Z0-9]/", function($matches)
         {
             return strtoupper($matches[0][1]);
         }, $string);
@@ -26,7 +26,7 @@ class LuStringUtils
     
     public static function camelCaseToSnake($string, $underscoreFirstCharacter)
     {
-        $str = preg_replace_callback("/[A-Z]/", function($matches)
+        $str = preg_replace_callback("/[A-Z0-9]/", function($matches)
         {
             return strtolower("_" . $matches[0]);
         }, $string);