Merge pull request DjangoGirls#1584 from kaizumaki/feature/note-about-tree

Indicate that directory venv is also there when showing where to put requirements.txt

Author: das-g

en/django_installation/instructions.md

@@ -183,6 +183,8 @@ First create a `requirements.txt` file inside of the `djangogirls/` folder, usin
 
 ```
 djangogirls
+├── myvenv
+│   └── ...
 └───requirements.txt
 ```