app/matrix add branding to matrix.0x3c.pl

Change-Id: Ib78a2dae0ed177d670ab760892896306363ed3e6
diff --git a/app/matrix/matrix.0x3c.pl.jsonnet b/app/matrix/matrix.0x3c.pl.jsonnet
index 504829a..3ecb2e4 100644
--- a/app/matrix/matrix.0x3c.pl.jsonnet
+++ b/app/matrix/matrix.0x3c.pl.jsonnet
@@ -16,4 +16,11 @@
             enabled: true,
         },
     },
+
+    riotConfig+:: {
+        "brand": "Element - %s" % [cfg.serverName],
+        "branding": {
+            "welcomeBackgroundUrl": "https://media.0x3c.pl/file/0x3c-mastodon/0x3c-pixelsort.png"
+        },
+    },
 }