Mars theme for generated admin account

db/fixtures/development/01_admin.rb

@@ -8,5 +8,6 @@ User.seed(:id, [
     password_confirmation: "5iveL!fe",
     admin: true,
     projects_limit: 100,
+    theme_id: Gitlab::Theme::MARS
   }
 ])

db/fixtures/production/001_admin.rb

@@ -4,7 +4,9 @@ admin = User.create(
   username: 'root',
   password: "5iveL!fe",
   password_confirmation: "5iveL!fe",
-  password_expires_at: Time.now
+  password_expires_at: Time.now,
+  theme_id: Gitlab::Theme::MARS
+
 )
 admin.projects_limit = 10000