Merge branch 'issue-13619' of https://0xacab.org/sutty/sutty into 17.3.alpine.panel.sutty.nl

app/models/site.rb

@@ -223,7 +223,9 @@ class Site < ApplicationRecord
   # colecciones.
   def collections
     unless @read
-      jekyll.reader.read_collections
+      Site.one_at_a_time.synchronize do
+        jekyll.reader.read_collections
+      end
 
       @read = true
     end
@@ -439,6 +441,10 @@ class Site < ApplicationRecord
     find_by(name: "#{Site.domain}.")
   end
 
+  def self.one_at_a_time
+    @@one_at_a_time ||= Thread::Mutex.new
+  end
+
   def reset
     @read = false
     @layouts = nil