Change the directory of Bootstrap from '_assets' to static 'assets'.

assets/vendor/bootstrap/.editorconfig

@@ -0,0 +1,14 @@
+# editorconfig.org
+
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.py]
+indent_size = 4