PYSCAN-50 Document the setup of poetry to pull dependencies from private artifactory repo (#38)

Author: Jeremi Do Dinh

README.md

@@ -139,7 +139,22 @@ Run `python src/py_sonar_scanner`
 
 # Run the tests
 
-Run `poetry install` to install the dependencies
+Run `poetry install` to install the dependencies. By default, the dependencies are installed from the Repox private repository.
+
+To configure your credentials for Repox, go to your Repox user profile, and generate an identity token. Then set the following two environment variables:
+```markdown
+export POETRY_HTTP_BASIC_REPOX_USERNAME=<username>
+export POETRY_HTTP_BASIC_REPOX_PASSWORD=<password>
+```
+Where `<username>` is your Repox username and `<password>` is the identity token you generated.
+
+If you wish to install the dependencies from the public PyPI repository, remove the following from `pyproject.toml`:
+```toml
+[[tool.poetry.source]]
+name = "repox"
+url = "https://repox.jfrog.io/artifactory/api/pypi/sonarsource-pypi/simple/"
+priority = "default"
+```
 
 ## Run the tests only