also set default tile sources when updating the project.

- this has the side effect that a project with the gtt module enabled can never
  have _no_ tile sources configured (since an empty set will be replaced with
  the defaults).

Author: jkraemer

lib/redmine_gtt/patches/project_patch.rb

@@ -8,7 +8,7 @@ def self.apply
           Project.class_eval do
             safe_attributes "geom"
             has_and_belongs_to_many :gtt_tile_sources
-            after_create :set_default_tile_sources
+            after_save :set_default_tile_sources
           end
         end
       end

test/unit/update_project_test.rb

@@ -0,0 +1,19 @@
+require_relative '../test_helper'
+
+class UpdateProjectTest < ActiveSupport::TestCase
+
+  test 'should add default tile source if module is enabled' do
+    ts = RedmineGtt::Actions::CreateTileSource.(type: 'ol.source.OSM', name: 'default', default: true).tile_source
+    RedmineGtt::Actions::CreateTileSource.(type: 'ol.source.OSM', name: 'not default', default: false)
+
+    p = Project.create! name: 'test project', identifier: 'test-project'
+    assert p.gtt_tile_sources.none? # module not enabled
+
+    p.update_attribute :enabled_module_names, ['gtt']
+    p.reload
+    assert_equal [ts], p.gtt_tile_sources.to_a
+  end
+
+end
+
+