Collect statistics

[kozalosev]

I want to know how many users are getting help by the bot. And where are they from.

Besides, collecting user IDs I would be able to send informational messages. I promise that this functionality won't be used for selling users' personal data or sending any advertisement messages.

[kozalosev]

There are some important questions to think of before starting the work:

• What information do I want to store? How will I get the data from the storage later?
• What storage do I need to use? Relational database? Timeseries database? Or something like MongoDB?
• Do I want to implement the same for @kozRandBot?

I think I need two tables/documents:

• user_id | count_of_queries_for_all_time
• date | count_of_queries_for_that_day

The relational model fits well but what about object mapping? Currently, the bot uses SQLite, but if I'm going to use this functionality for another bot it would be better to use a standalone database like PostgreSQL, wouldn't it?

I wish to take a break for some time and consider these things more carefully. So, this feature and #12 will be implemented in the next milestone.