add read users list

msql_acces.h

@@ -14,6 +14,7 @@ public:
   msql_acces();
   std::string get_passwd(std::string username);
   std::list<std::string> get_pinfo();
+  std::list<std::string> get_uinfo();
   void write_install(std::string package, std::string user);
   void write_remove(std::string);
   bool get_package_exists(std::string package);