old_contents: from keywords import get_db
  
  db = get_db()
  
  tweets = db.tweets
  stories = db.stories
  
  tweets.create_index([("num_keywords", 1), ("datetime", 1)])  # api:/keywords, statistics.py
  tweets.create_index([("groups", 1), ("datetime", 1)])        # api:/keywords, api:/groups/{group}
  tweets.create_index([("keywords", 1), ("datetime", 1)])      # api:/keywords/{keyword}/*
  tweets.create_index("tweet.id_str")                          # api:/tweet/{id_str}
  
  storiesdb.create_index([("groups", 1), ("datetime", 1)])
  
new_contents: from keywords import get_db
  
  db = get_db()
  
  tweets = db.tweets
  stories = db.stories
  
  tweets.create_index([("num_keywords", 1), ("datetime", 1)])  # api:/keywords, statistics.py
  tweets.create_index([("groups", 1), ("datetime", 1)])        # api:/keywords, api:/groups/{group}
  tweets.create_index([("keywords", 1), ("datetime", 1)])      # api:/keywords/{keyword}/*
  tweets.create_index("tweet.id_str")                          # api:/tweet/{id_str}
  
  stories.create_index([("groups", 1), ("datetime", 1)])       # storify.py:load_stories
  
subject: fix index