add Local development documentation

README.md

@@ -1,8 +1,8 @@
 # ![icon](https://raw.githubusercontent.com/bjornFJohansson/pydna/master/docs/pics/pydna.resized.png) pydna
 
-| [![Tests & Coverage](https://github.com/BjornFJohansson/pydna/actions/workflows/pydna_test_and_coverage_workflow.yml/badge.svg?branch=dev_bjorn)](https://github.com/BjornFJohansson/pydna/actions/workflows/pydna_test_and_coverage_workflow.yml) | [![codecov](https://codecov.io/gh/BjornFJohansson/pydna/branch/master/graph/badge.svg)](https://codecov.io/gh/BjornFJohansson/pydna/branch/master) | [![PyPI version](https://badge.fury.io/py/pydna.svg)](https://badge.fury.io/py/pydna)    | [![Google group : pydna](https://img.shields.io/badge/Google%20Group-pydna-blue.svg)](https://groups.google.com/g/pydna)              |
-|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------|
-| [![Documentation Status](https://readthedocs.org/projects/pydna/badge/?version=latest)](http://pydna.readthedocs.io/?badge=latest)                                                                   | [![GitHub issues](https://img.shields.io/github/issues/BjornFJohansson/pydna.svg)](https://github.com/BjornFJohansson/pydna/issues)                | [![Anaconda-Server Badge2](https://anaconda.org/bjornfjohansson/pydna/badges/license.svg)](https://anaconda.org/bjornfjohansson/pydna) | [![GitHub stars](https://img.shields.io/github/stars/BjornFJohansson/pydna.svg)](https://github.com/BjornFJohansson/pydna/stargazers) |
+| [![Tests & Coverage](https://github.com/BjornFJohansson/pydna/actions/workflows/pydna_test_and_coverage_workflow.yml/badge.svg?branch=dev_bjorn)](https://github.com/BjornFJohansson/pydna/actions/workflows/pydna_test_and_coverage_workflow.yml) | [![codecov](https://codecov.io/gh/BjornFJohansson/pydna/branch/master/graph/badge.svg)](https://codecov.io/gh/BjornFJohansson/pydna/branch/master) | [![PyPI version](https://badge.fury.io/py/pydna.svg)](https://badge.fury.io/py/pydna)                                                  | [![Google group : pydna](https://img.shields.io/badge/Google%20Group-pydna-blue.svg)](https://groups.google.com/g/pydna)              |
+| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
+| [![Documentation Status](https://readthedocs.org/projects/pydna/badge/?version=latest)](http://pydna.readthedocs.io/?badge=latest)                                                                                                                 | [![GitHub issues](https://img.shields.io/github/issues/BjornFJohansson/pydna.svg)](https://github.com/BjornFJohansson/pydna/issues)                | [![Anaconda-Server Badge2](https://anaconda.org/bjornfjohansson/pydna/badges/license.svg)](https://anaconda.org/bjornfjohansson/pydna) | [![GitHub stars](https://img.shields.io/github/stars/BjornFJohansson/pydna.svg)](https://github.com/BjornFJohansson/pydna/stargazers) |
 
 
 
@@ -193,7 +193,7 @@ Pydna is importable even without these two modules.
 If the modules listed below in the first column are installed, they will provide the functionality listed in the second column.
 
 | Dependency                                          | Function in pydna                                      |
-|-----------------------------------------------------|--------------------------------------------------------|
+| --------------------------------------------------- | ------------------------------------------------------ |
 | [scipy](https://www.scipy.org)                      | gel simulation with pydna.gel                          |
 | [matplotlib](http://matplotlib.org)                 | “                                                      |
 | [pillow](https://github.com/python-pillow/Pillow)   | “                                                      |
@@ -234,6 +234,27 @@ or by `pip install scipy matplotlib pillow pyparsing requests cai2 pyqt5`
 
 ![----]( http://bit.ly/coloredline)
 
+## Contributing
+
+### Local development
+
+1. Use [Poetry](https://pypi.org/project/poetry) to install depencies and activate virtual environment.
+
+    ```bash
+    # If you want the virtual environment to be created in this folder
+    poetry config virtualenvs.in-project true
+
+    # Install dependencies (extras are required for tests to pass)
+    poetry install --all-extras
+
+    # Activate virtual environment
+    poetry shell
+    ```
+
+2. Make your changes.
+3. Add the necessary tests in `tests/`.
+4. Run the tests from the root directory with `python run_test.py`.
+
 ## Releases
 
 See the [releases](https://github.com/BjornFJohansson/pydna/releases) for changes and releases.