public async Task <DictionaryModel> CreateDictionary(Guid userId, DictionaryModel dictionaryModel)
        {
            var language = await Db.Languages.FirstOrDefaultAsync(l => l.Name.Equals(dictionaryModel.SourceLanguage));

            var dictionary = dictionaryModel.ToEntity(language ?? new Language
            {
                Name = dictionaryModel.SourceLanguage
            });

            dictionary.UserDictionaries.Add(new ApplicationUserDictionary
            {
                ApplicationUserId = userId,
                IsOwner           = true,
                IsStudied         = false
            });

            await Db.Dictionaries.AddAsync(dictionary);

            await Db.SaveChangesAsync();

            return(dictionary.ToDto(false));
        }