Add fields 'total_rounds' and 'current_round' to Tournament model.
Develop some methods for calculate total_rounds.
Overrige TournamentsAdmin get_form method.

On branch dev
	modified:   main/admin.py
	new file:   main/migrations/0005_auto__add_field_tournament_total_rounds__add_field_tournament_current_.py
	modified:   main/models.py
Refactore code: move code from main.admin module to main.admin package for improve usability.
Add additional urls in 'get_urls' methods in TournamentResultAdmin and GameAdmin classes.
Add new methods 'tournament_changelist_view' to TournamentResultAdmin and GameAdmin classes.
Add additional links in 'tournament/change_form.html' template.
Modify 'game/changelist.html' and 'tournamentresult/changelist.html' for adding selected tournament information.

Create a new ModelAdminExt() ModelAdmin instance for manage selected tournament.

On branch dev
	modified:   chess/urls.py
	deleted:    main/admin.py
	new file:   main/admin/__init__.py
	new file:   main/admin/game.py
	new file:   main/admin/player.py
	new file:   main/admin/tournament.py
	new file:   main/admin/tournament_result.py
	new file:   main/admin/utils.py
	modified:   main/models.py
	new file:   main/templates/admin/main/game/change_list.html
	new file:   main/templates/admin/main/tournament/change_form.html
	new file:   main/templates/admin/main/tournamentresult/change_list.html
Modify field referee in table main_game.
Develop creating games functionality for first round.
Add method 'recalc_rating' to Game class.

On branch dev
	modified:   chess/urls.py
	modified:   main/admin/game.py
	new file:   main/migrations/0006_auto__chg_field_game_referee.py
	modified:   main/models.py
	modified:   main/templates/admin/main/game/change_list.html
	modified:   main/templates/admin/main/tournament/change_form.html