feat: make email client send requests

src/email_client.rs

@@ -30,7 +30,7 @@ impl EmailClient {
         subject: &str,
         html_content: &str,
         text_content: &str,
-    ) -> Result<(), String> {
+    ) -> Result<(), reqwest::Error> {
         // TODO: use `reqwest::Url::join` and change `base_url`'s type from `String` to `reqwest::Url`
         let url = format!("{}/email", self.base_url);
         let request_body = SendEmailRequest {
@@ -47,7 +47,9 @@ impl EmailClient {
                 "X-Postmark-Server-Token",
                 self.authorization_token.expose_secret(),
             )
-            .json(&request_body);
+            .json(&request_body)
+            .send()
+            .await?;
         Ok(())
     }
 }