Update model database schema

Elwig/Helpers/Utils.cs

@@ -86,5 +86,13 @@ namespace Elwig.Helpers {
                 UseShellExecute = true,
             });
         }
+
+        public static double KmwToOe(double kmw) {
+            return Math.Round(kmw * (4.54 + 0.022 * kmw), 0);
+        }
+
+        public static double OeToKmw(double oe) {
+            return Math.Round((-4.54 + Math.Sqrt(4.54 * 4.54 - 4 * 0.022 * -oe)) / 2 * 0.022, 1);
+        }
     }
 }