public void AddGroup(string groupName, string groupID)
{
string json = null;
using (var streamReader = new StreamReader(fullPath))
{
json = streamReader.ReadToEnd();
Console.WriteLine(json);
}
UserDB tempUser = JsonConvert.DeserializeObject <UserDB>(json);
tempUser.AddGroup(groupName, groupID);
string jsonConversiton = JsonConvert.SerializeObject(tempUser);
File.WriteAllText(fullPath, jsonConversiton);
}