MAPG-235 reduced number of queries for init and guess in challenge

src/Repository/PlaceInChallengeRepository.php

@@ -40,4 +40,14 @@ class PlaceInChallengeRepository
 
         return $this->pdm->selectFromDb($select, PlaceInChallenge::class);
     }
+
+    public function getByRoundInChallenge(int $round, Challenge $challenge): ?PlaceInChallenge
+    {
+        $select = new Select(\Container::$dbConnection);
+        $select->where('challenge_id', '=', $challenge->getId());
+        $select->orderBy('round');
+        $select->limit(1, $round);
+
+        return $this->pdm->selectFromDb($select, PlaceInChallenge::class, true);
+    }
 }