Added FK 'ContactId' (optional/nullable).

Nullable property = optional relationship.

Gremlin/GremlinData/EntityClasses/Quote.cs

@@ -9,12 +9,12 @@ namespace Gremlin.GremlinData.EntityClasses
         public uint QuoteId { get; set; }
 
         //foreign keys:
+        public uint? ContactId { get; set; }
+        
+        //navigation properties:
         public Contact Recipient { get; set; }
         public IList<LineItem> LineItems { get; set; }
-
+                
-        //navigation properties:
-        //NONE
-
         //class properties:
         public Contact SalesRep { get; set; }
         public string QuotationNumber { get; set; }