reference to poetry in readme

TODO.md

@@ -1,6 +1,5 @@
 # TODO:
 
-- edit readme to use poetry
 - tests
 - add AGPL
 - add CI

{{ cookiecutter.project_slug }}/.gitignore

@@ -26,6 +26,7 @@ wheels/
 *.egg
 
 # virtualenv
+.venv/
 venv/
 
 # mypy

{{ cookiecutter.project_slug }}/README.md

@@ -18,13 +18,14 @@ This project if a free software released under the {{ cookiecutter.open_source_l
 
 ## Dev
 
-If you want to tinker with this project, you can clone it and install it in editable mode:
+This project is managed by [poetry](https://python-poetry.org/).
 
+To open a shell in a venv of the project: 
 ```
 git clone {{ cookiecutter.project_url }}.git
 cd {{ cookiecutter.project_slug }}
-python -m venv venv && source venv/bin/activate
+poetry shell
-pip install -e .[dev]
+poetry install
 ```
 
 ### Test