fix(ActiveRecord): correctly connect to the database in Rails 7.2+

lib/slack-ruby-bot-server/config/database_adapters/activerecord.rb

@@ -6,7 +6,12 @@
 module SlackRubyBotServer
   module DatabaseAdapter
     def self.check!
-      ActiveRecord::Base.connection_pool.with_connection(&:active?)
+      if ActiveRecord::VERSION::STRING >= "7.2"
+        raise "Database does not exist." unless ActiveRecord::Base.connection.database_exists?
+      else
+        ActiveRecord::Base.connection_pool.with_connection(&:active?)
+      end
+
       raise 'Unexpected error.' unless ActiveRecord::Base.connected?
     rescue StandardError => e
       warn "Error connecting to PostgreSQL: #{e.message}"