Search: Save detected pg version in a persistent term.

lib/pleroma/activity/search.ex

@@ -20,7 +20,7 @@ defmodule Pleroma.Activity.Search do
     author = Keyword.get(options, :author)
 
     search_function =
-      if Application.get_env(:postgres, :version) >= 11 do
+      if :persistent_term.get({Pleroma.Repo, :postgres_version}) >= 11 do
         :websearch
       else
         :plain

lib/pleroma/application.ex

@@ -131,7 +131,7 @@ defmodule Pleroma.Application do
           9.6
       end
 
-    Application.put_env(:postgres, :version, version)
+    :persistent_term.put({Pleroma.Repo, :postgres_version}, version)
   end
 
   def load_custom_modules do