def join_tweets_users(df_tweet, df_user):
    """ Joins a dataframe of tweets with a dataframe of users by matching user ids to tweets

    Args:
        df_tweet (DataFrame): A dataframe containing tweet text with user ids
        df_user (DataFrame): A dataframe containing user name and id
        
    Returns:
        df_tweet_user (DataFrame): A dataframe containing tweet text, user id, and user name
    """
    
    df_tweet_user = df_tweet.merge(df_user, on='user_id', how='left')
    
    return df_tweet_user