restore untested $LOAD_PATH behavior, add tests, fixes #1463

Author: ujifgc

padrino-core/lib/padrino-core/loader.rb

@@ -169,6 +169,7 @@ def require_dependencies(*paths)
     #
     def set_load_paths(*paths)
       load_paths.concat(paths).uniq!
+      $LOAD_PATH.concat(paths).uniq!
     end
 
     ##

padrino-core/test/test_reloader_system.rb

@@ -39,5 +39,14 @@ def shmamily
         File.open(parent_file, "w") { |f| f.write(backup) }
       end
     end
+    
+    should 'tamper with LOAD_PATH' do
+      SystemDemo.load_paths.each do |lib_dir|
+        assert_includes $LOAD_PATH, lib_dir
+      end
+      Padrino.send(:load_paths_was).each do |lib_dir|
+        assert_includes $LOAD_PATH, lib_dir
+      end
+    end
   end
 end