Add empty constructors to allow JSON serialization

server/Models/Database/StationListing.cs

@@ -13,5 +13,6 @@ public record StationListing(
     string Name,
     List<string> StoppedAtBy
 ) {
+    public StationListing() : this(null, "", new()) { }
     public StationListing(string name, List<string> stoppedAtBy) : this(null, name, stoppedAtBy) { }
 }

server/Models/Database/TrainListing.cs

@@ -13,5 +13,6 @@ public record TrainListing(
     string Number,
     string Company
 ) {
+    public TrainListing() : this(null, "", "", "") { }
     public TrainListing(string rank, string number, string company) : this(null, rank, number, company) { }
 }