LDAP: add delete_all_users method, use in seeds

app/services/ldap_service.rb

@@ -34,14 +34,17 @@ class LdapService < ApplicationService
     client.delete dn: dn
     client.get_operation_result.code
   end
+
+  def delete_all_users!
+    delete_all_entries!(objectclass: "person")
   end
 
-  def delete_all_entries!
+  def delete_all_entries!(objectclass: "*")
     if Rails.env.production?
       raise "Mass deletion of entries not allowed in production"
     end
 
-    filter  = Net::LDAP::Filter.eq("objectClass", "*")
+    filter  = Net::LDAP::Filter.eq("objectClass", objectclass)
     entries = client.search(base: @suffix, filter: filter, attributes: %w{dn})
     entries.sort_by!{ |e| e.dn.length }.reverse!