Merge pull request #1881 from tactilenews/refactor-avoid-null-byte-ch…

…aracters

refactor: avoid null-byte characters

spec/factories/contributors.rb

@@ -20,7 +20,7 @@
     trait :threema_contributor do
       after(:build) do |contributor|
         contributor.email = nil
-        contributor.threema_id = Faker::String.random(length: 8)
+        contributor.threema_id = Faker::Alphanumeric.alpha(number: 8)
       end
     end