feat(mailer): send mail asynchronously

Signed-off-by: SphericalKat <amolele@gmail.com>

config/prod.exs

@@ -16,32 +16,6 @@ config :ketbin, KetbinWeb.Endpoint,
 # Do not print debug messages in production
 config :logger, level: :info
 
-smtp_relay =
-  System.get_env("SWOOSH_SMTP_RELAY") ||
-    raise """
-    environment variable SWOOSH_SMTP_RELAY is missing.
-    """
-username =
-  System.get_env("SWOOSH_USERNAME") ||
-    raise """
-    environment variable SWOOSH_USERNAME is missing.
-    """
-password =
-  System.get_env("SWOOSH_PASSWORD") ||
-    raise """
-    environment variable SWOOSH_PASSWORD is missing.
-    """
-
-# configure mailer
-config :ketbin, Ketbin.Mailer,
-  adapter: Swoosh.Adapters.SMTP,
-  relay: smtp_relay,
-  username: username,
-  password: password,
-  tls: :always,
-  auth: :always,
-  port: 587
-
 # ## SSL Support
 #
 # To get SSL working, you will need to add the `https` key

config/releases.exs

@@ -33,6 +33,31 @@ config :ketbin, KetbinWeb.Endpoint,
   secret_key_base: secret_key_base,
   server: true
 
+  smtp_relay =
+    System.get_env("SWOOSH_SMTP_RELAY") ||
+      raise """
+      environment variable SWOOSH_SMTP_RELAY is missing.
+      """
+  username =
+    System.get_env("SWOOSH_USERNAME") ||
+      raise """
+      environment variable SWOOSH_USERNAME is missing.
+      """
+  password =
+    System.get_env("SWOOSH_PASSWORD") ||
+      raise """
+      environment variable SWOOSH_PASSWORD is missing.
+      """
+
+  # configure mailer
+  config :ketbin, Ketbin.Mailer,
+    adapter: Swoosh.Adapters.SMTP,
+    relay: smtp_relay,
+    username: username,
+    password: password,
+    tls: :always,
+    auth: :always,
+    port: 587
 # ## Using releases (Elixir v1.9+)
 #
 # If you are doing OTP releases, you need to instruct Phoenix