Implemented YandexRequester summary method (TODO: test it)
Added BotData struct that will replace the Settings struct in the future
Implemented update methods for some structs' tables in BotData (TODO: implement update_requester and new methods)
Moved migrations to root directory
Note: use sqlx-cli from cargo to manage migrations from now on
Added *.db files to .gitignore
Added serde_json to Cargo.toml to parse json in YandexRequester
