Add the initial glicko history point with the old elo of the first TeamGlickoHistory row

Author: jaeheonshim

src/main/java/org/bytefight/webserver/glicko/domain/dto/TeamGlickoHistoryDto.java

@@ -25,6 +25,12 @@ public static TeamGlickoHistoryDto from(
     List<Long> timestamps = new ArrayList<>(histories.size());
     List<Double> glickos = new ArrayList<>(histories.size());
 
+    if(!histories.isEmpty()) {
+      TeamGlickoHistory initial = histories.get(0);
+      timestamps.add(team.getCreatedAt().getEpochSecond());
+      glickos.add(initial.getOldGlicko());
+    }
+
     for (TeamGlickoHistory h : histories) {
       timestamps.add(h.getCreatedAt().getEpochSecond());
       glickos.add(h.getNewGlicko());