add documentation for a development setup

README.md

-# Django application server
+# DALIA's backend Django application server
+
+## Development setup
+
+### Requirements
+
+* Python 3 (Which version? ... Works in 3.11)
+* pip
+* Docker (if using Testcontainers in tests)
+
+### Setup
+
+Clone this repo:
+```shell
+git clone https://git.rwth-aachen.de/dalia/backend/django.git
+```
+
+Create and activate a virtual environment:
+```shell
+cd django
+python3 -m venv .env
+source .env/bin/activate
+```
+
+Install dependencies:
+```shell
+pip install -r requirements-dev.txt
+```
+
+### Running tests using Testcontainers
+
+[Testcontainers](https://testcontainers.com/) is used to provide [DALIA's Fuseki triplestore](https://git.rwth-aachen.de/dalia/backend/fuseki) as dependency during tests via the `triplestore` pytest fixture.
+
+To run tests:
+```shell
+pytest
+```
+
+### Running tests using a custom triplestore URL
+
+The `triplestore` pytest fixture can also be configured to use a custom URL to [DALIA's Fuseki triplestore](https://git.rwth-aachen.de/dalia/backend/fuseki). This can be achieved by using the `TRIPLESTORE_URL` environment variable.
+
+To run tests:
+```shell
+TRIPLESTORE_URL="http://127.0.0.1:3030/" pytest
+```
+
+### Starting Django in "development mode"
+
+Note: You may need to alter `DALIA_TRIPLESTORE_BASE_URL` in [project/settings.py](project/settings.py) to the correct address of [DALIA's Fuseki triplestore](https://git.rwth-aachen.de/dalia/backend/fuseki).
+
+To start Django:
+```shell
+./manage.py runserver 0.0.0.0:8000
+```