Fix Member: Add ? to RdNr

Elwig/Models/AreaCom.cs

@@ -28,7 +28,7 @@ namespace Elwig.Models {
         public string GstNr { get; set; }
 
         [Column("rdnr")]
-        public int RdNr { get; set; }
+        public int? RdNr { get; set; }
 
         [Column("year_from")]
         public int YearFrom { get; set; }

Elwig/Models/Member.cs

@@ -165,7 +165,7 @@ namespace Elwig.Models {
         public virtual ISet<AreaCom> AreaCommitments { get; private set; }
 
         [NotMapped]
-        public virtual IEnumerable<AreaCom> ActiveAreaCommitments => AreaCommitments
+        public IEnumerable<AreaCom> ActiveAreaCommitments => AreaCommitments
             .Where(c => c.YearFrom <= Utils.CurrentSeason && (c.YearTo ?? int.MaxValue) >= Utils.CurrentSeason);
 
         [InverseProperty("Member")]