Change path to database in model to reflect that database is in parent directory.
Add docstrings and more semantic naming to hashtags.py

 - rename starting hashtags to SEED hashtags
 - add docstrings to functions, particularly load_hashtags
Update seed_tweets.py with extended lists of p and np hashtags, remove parameters no longer needed by moving hashtag collection to separate file.
Database with approx half political, half nonpoitical tweets. Predates the addition of co-occurring nonpolitical hashtags.
Most current db, still with approx 50-50 np-p tweets despite adding co-occurring nonpolitical tweets. 36,000 unique records.
Made backup copy of tweets database (with 36000 entries) before I erase database and re-seed