Use less busy default background.

CONTRIBUTORS.md

@@ -4,6 +4,7 @@ Contributors of this project.
 - Coco Snuss (cocosnuss@social.heldscal.la): Code
 - wakarimasen (wakarimasen@shitposter.club): NSFW hiding image
 - dtluna (dtluna@social.heldscal.la): Code
-- sonyam (sonyam@social.heldscal.la): Default background image
+- sonyam (sonyam@social.heldscal.la): Background images
 - hakui (hakui@freezepeach.xyz): CSS and styling
-- shpuld (shpuld@shitposter.club): CSS and styling
\ No newline at end of file
+- shpuld (shpuld@shitposter.club): CSS and styling
+- Vincent Guth (https://unsplash.com/photos/XrwVIFy6rTw): Background images.

static/config.json

 {
   "theme": "pleroma-dark",
-  "background": "/static/bg.jpg",
+  "background": "/static/aurora_borealis.jpg",
   "logo": "/static/logo.png",
   "defaultPath": "/main/all",
   "chatDisabled": false,