.convert rewritten a bit, isn't saved in the database anymore, but in redis.

NadekoBot.Core/Modules/Utility/Common/ConvertUnit.cs

@@ -0,0 +1,9 @@
+namespace NadekoBot.Modules.Utility.Common
+{
+    public class ConvertUnit
+    {
+        public string[] Triggers { get; set; }
+        public string UnitType { get; set; }
+        public decimal Modifier { get; set; }
+    }
+}