Move 'domain' into config.yml

config/config.yml

@@ -10,3 +10,4 @@ db:
   dbname: invidious
 full_refresh: false
 https_only: false
+domain: invidio.us

src/invidious/helpers/helpers.cr

@@ -15,10 +15,7 @@ class Config
     https_only:   Bool?,
     hmac_key:     String?,
     full_refresh: Bool,
-    domain:       {
-      type:    String?,
-      default: "invidio.us",
-    },
+    domain:       String,
   })
 end