feature: expression helpers - basic email sending

Disco.Services/Expressions/Extensions/EmailExt.cs

@@ -0,0 +1,32 @@
+using Disco.Models.Repository;
+using Disco.Models.Services.Messaging;
+using Disco.Services.Messaging;
+using System;
+
+namespace Disco.Services.Expressions.Extensions
+{
+    public static class EmailExt
+    {
+        public static void SendToUser(User user, string subject, string body)
+        {
+            var to = user.EmailAddress;
+
+            if (string.IsNullOrWhiteSpace(to))
+                throw new Exception($"User ({user.UserId}) does not have an email address");
+
+            Send(to, subject, body);
+        }
+
+        public static void Send(string to, string subject, string body)
+        {
+            var email = new Email()
+            {
+                Subject = subject,
+                Body = body,
+            };
+            email.To.Add(to);
+
+            EmailService.SendEmail(email);
+        }
+    }
+}