Update model database schema

Elwig/Models/Currency.cs

@@ -0,0 +1,22 @@
+using Microsoft.EntityFrameworkCore;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Elwig.Models {
+    [Table("currency"), PrimaryKey("Code")]
+    public class Currency {
+        [Column("code")]
+        public string Code { get; private set; }
+
+        [Column("name")]
+        public string Name { get; private set; }
+
+        [Column("symbol")]
+        public string? Symbol { get; private set; }
+
+        [Column("one_euro")]
+        public int? OneEuroValue { get; private set; }
+
+        [NotMapped]
+        public decimal? OneEuro => OneEuroValue / 1_000_000;
+    }
+}