Add Spring to pom.xml
Add Hibernate and MySQL connector to pom.xml
Add domain objects
Add Spring configuration file
Create tweet listener

TweetListener consumes tweet stream, and persists incoming tweets in
the database.
Add application fetching tweet specified by ID
Add computing recommendation statistics

Application iterates over the tweets in the database, and for each
calculates number of users recommended in the tweet body. Creates
histogram of recommendation counts per tweet.

Important: It utilizes Hibernate ScrollableResults API, in order to
avoid loading the whole table to memory, which turns out to be
prohibitively expensive.
Change DB name to TwitterV2
Enable unicode in the DB
Add logging facilities to pom.xml
Remove garbage from Application.java
Remove printTweet from TweetListener
Revamp persistence layer

Changes slightly design of domain objects, and modifies TweetListener
accordingly.
Migrate to SpringBoot
Add flags for different types of users and tweets
Add proper handling of status deletion
Add setting tweet & user flags + language filter
Add counting and listing methods to BaseDAO
Add tweet count reporter

TweetCountReporter is a task scheduled every 10 seconds, that outputs
to log current number of users and tweets in the database.
Remove obsolete TweetDAO.getTweets()