Error handling refactor and 500 page/message templates

src/domain/subscriber_email.rs

@@ -7,11 +7,11 @@ pub struct SubscriberEmail {
 }
 
 impl SubscriberEmail {
-    pub fn parse(email: String) -> Result<Self, String> {
+    pub fn parse(email: String) -> Result<Self, anyhow::Error> {
         let subscriber_email = SubscriberEmail { email };
-        subscriber_email
-            .validate()
-            .map_err(|_| format!("{} is not a valid email.", subscriber_email.email))?;
+        if subscriber_email.validate().is_err() {
+            anyhow::bail!("{} is not a valid email.", subscriber_email.email);
+        }
         Ok(subscriber_email)
     }
 }