code: function MongoDB(host, port, database, collection, username, password){
          _self = this;
  
          if(arguments.length < 3){
              throw ("MongoDB constructor requires at least three arguments!");
          }
  
          if(collection){
              _collection = collection;
          } else{
              _collection = DEFAULT_COLLECTION_NAME;
          }
  
          _username = username;
          _password = password;
  
          _host = host;
  
          //create new database connection
          _db = new Db(database, new Server(host, port), {safe:false}, {auto_reconnect: true});
      }
docs: Wrapper class for MongoDB for use with the Blocker modules.
  Host and port specify on which computer MongoDB is running.
  @param host Host of the database which shall be used for the Blocklist.
  @param port Number of the port which shall be used for the Blocklist.
  @param database Name of the database which shall be used for the Blocklist.
  @param collection Name of the collection that shall be used for the Blocklist.
  @param username optional parameter for username to connect to database.
  @param password optional parameter for password to connect to database.
  @attention This class is permanently holding a connection to the database.