public void SaveWordDict(HashSet <string> words)
        {
            MongoCollection <WordIDF> collection = mongo_database.GetCollection <WordIDF>("words");

            foreach (string w in words)
            {
                WordIDF wi = new WordIDF();
                wi.word = w;
                wi.idf  = 0;
                collection.Insert <WordIDF>(wi);
            }
        }
 public void SaveWordDict(HashSet<string> words)
 {
     MongoCollection<WordIDF> collection = mongo_database.GetCollection<WordIDF>("words");
     foreach (string w in words)
     {
         WordIDF wi = new WordIDF();
         wi.word = w;
         wi.idf = 0;
         collection.Insert<WordIDF>(wi);
     }
 }