Fix approved column being set to nil instead of false (mastodon#10642)

Gargron · hiyuki2578 · commit 171fb02fbd0a · 2019-10-02T11:26:39.000+09:00
Fix mastodon#10621 (comment)
diff --git a/app/models/user.rb b/app/models/user.rb
@@ -282,7 +282,7 @@ def open_registrations?
   end
 
   def external?
-    @external
+    !!@external
   end
 
   def sanitize_languages
