Keep extra saved versions for Tiddlyspot sites

The idea is Tiddlyspot sites are legacy and deprecated, so I'm
intentionally not adding all the features of Tiddlyhost sites, but
there are some folks still using them. If they manage to break their
site somehow, having previous versions available helps me help them
to get it back to a working version.

There'll be some impact on the storage I guess, but I'm not too
worried about that.

Author: simonbaird

rails/app/models/tspot_site.rb

@@ -152,8 +152,10 @@ def redirect_tspot_to_url_enabled?
     Settings.feature_enabled?(:redirect_tspot_to_url, user)
   end
 
-  # No site history for tspot sites
+  # For legacy Tiddlyspot sites we don't provide the site history
+  # feature, but let's one keep some previous versions so we can
+  # help users recover from a broken save.
   def keep_count
-    1
+    Settings.keep_counts[:tiddlyspot]
   end
 end

rails/config/settings.yml

@@ -50,6 +50,7 @@ defaults:
   keep_counts:
     :free: 4
     :standard: 100
+    :tiddlyspot: 4
 
 development:
   url_defaults: