allow simple underline

closes #190

src/strass/strass_app/templatetags/strass_tags.py

@@ -216,6 +216,8 @@ __MARKDOWN_WHITE_LIST = [
         '</center>',
         '<code>',
         '</code>',
+        '<u>',
+        '</u>',
     ]
 ]
 

src/strass/strass_app/tests/test_strass_tags.py

@@ -115,12 +115,15 @@ class AllTestCase(TooledTestCase):
             "<script",
             "<meta",
             "<img",
+            "<u"
         ]:
             self.assertNotIn(banned_tag, markdown(f'{banned_tag} foo="bar"/>'))
         for allowed_tag in [
             "<center>",
             "<br>",
             "<br/>",
+            "<u>",
+            "</u>",
             "<hr>",
             "<hr/>",
         ]: