FIX: Use a mutex when reseting column information while seeding.

`rake multisite:migrate` runs SeedFu concurently in threads so we need
this to be thread safe.

db/fixtures/001_refresh.rb

@@ -1,9 +1,13 @@
 # frozen_string_literal: true
 
 class SeedData::Refresher
+  @mutex = Mutex.new
+
   def self.refresh!
     return if @refreshed
 
+    @mutex.synchronize do
+      return if @refreshed
       # Fix any bust caches post initial migration
       # Not that reset_column_information is not thread safe so we have to becareful
       # not to run it concurrently within the same process.
@@ -13,6 +17,7 @@ class SeedData::Refresher
 
       @refreshed = true
     end
+  end
 end
 
 SeedData::Refresher.refresh!