The Army-Navy game has made some rare offseason headlines in the last few weeks — not for any on-field reasons, but as an inconvenient outlier for college football’s new playoff system. For Army West Point and Navy fans whose college football season begins and ends on the same Saturday in December, here’s a quick primer: The rankings that determine which teams will play in the College Football Playoff, and the four other top-tier bowl games played on or before New Year’s, come out the weekend before the Army-Navy game. Last year, this simply meant the rankings ignored the game, but that…