🔧(demo) Allow setting demo site domain so it is not localhost:8080

On our demo site, the site domain always ended-up as localhost:8080.
It was because we override it with a default value while building
the demo site.

sites/demo/CHANGELOG.md

@@ -8,6 +8,10 @@ Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Fixed
+
+- Allow setting demo site domain otherwise so it is not set to localhost:8080
+
 ## [1.11.0] - 2021-05-03
 
 ### Changed

sites/demo/src/backend/demo/settings.py

@@ -468,7 +468,9 @@ class Base(StyleguideMixin, DRFMixin, RichieCoursesConfigurationMixin, Configura
     }
 
     # Demo
-    RICHIE_DEMO_SITE_DOMAIN = "localhost:8080"
+    RICHIE_DEMO_SITE_DOMAIN = values.Value(
+        default="localhost:8080", environ_name="RICHIE_DEMO_SITE_DOMAIN", environ_prefix=None
+    )
     RICHIE_DEMO_FIXTURES_DIR = os.path.join(BASE_DIR, "base", "fixtures")
 
     # Elasticsearch