Update the contributing doc

CONTRIBUTING.md

@@ -2,19 +2,43 @@
 
 We love pull requests. Here's a quick guide.
 
-Fork, then clone:
-
-```bash
-git clone [email protected]:your-username/datadog-lambda-python.git
-```
-
-Make your change, update tests and ensure the tests pass (install Docker if you haven't):
-
-```bash
-./scripts/run_tests.sh
-```
-
-Push to your fork and [submit a pull request][pr].
+1. Fork, clone and branch off `main`:
+    ```bash
+    git clone [email protected]:<your-username>/datadog-lambda-python.git
+    git checkout -b <my-branch>
+    ```
+1. Make your changes. Ensure your code is compatible with both Python 2.7 and 3.X. 
+1. Test your Lambda function against the locally modified version of Datadog Lambda library.
+   * The easiest approach is to create a soft link of the `datadog_lambda` folder in your project's root. Note, this only overrides the `datadog_lambda` module, and you still need to install the `datadog_lambda` package or the Lambda layer to have the required dependencies.
+
+     ```bash
+     ln -s /PATH/TO/datadog-lambda-python/datadog_lambda /PATH/TO/MY/PROJECT
+     ```
+   * Another option is to install the `datadog_lambda` module from the local folder. E.g., add `/PATH/TO/datadog-lambda-python/` to your `requirements.txt`. This approach only work in a Linux environment, because the dependency `ddtrace` utilizes the native C extension.
+   * You can also build and publish a Lambda layer to your own AWS account and use it for testing.
+
+     ```bash
+     # Build layers using docker
+     ./scripts/build_layers.sh
+
+     # Publish the a testing layer to your own AWS account, and the ARN will be returned
+     # Example: ./scripts/publish_layers.sh us-east-1 Datadog-Python37
+     ./scripts/publish_layers.sh <AWS_REGION> <Layer_Name>
+     ```
+
+1. Ensure the unit tests pass (install Docker if you haven't):
+    ```bash
+    ./scripts/run_tests.sh
+    ```
+1. Run the integration tests against your own AWS account and Datadog org (or ask a Datadog member to run):
+   ```bash
+   BUILD_LAYERS=true DD_API_KEY=<your Datadog api key> ./scripts/run_integration_tests.sh
+   ```
+1. Update integration test snapshots if needed:
+   ```bash
+   UPDATE_SNAPSHOTS=true DD_API_KEY=<your Datadog api key> ./scripts/run_integration_tests.sh
+   ```
+1. Push to your fork and [submit a pull request][pr].
 
 [pr]: https://github.com/your-username/datadog-lambda-python/compare/DataDog:main...main
 

README.md

@@ -3,7 +3,7 @@
 ![build](https://github.com/DataDog/datadog-lambda-python/workflows/build/badge.svg)
 [![PyPI](https://img.shields.io/pypi/v/datadog-lambda)](https://pypi.org/project/datadog-lambda/)
 ![PyPI - Python Version](https://img.shields.io/pypi/pyversions/datadog-lambda)
-[![Slack](https://img.shields.io/badge/slack-%23serverless-blueviolet?logo=slack)](https://datadoghq.slack.com/channels/serverless/)
+[![Slack](https://chat.datadoghq.com/badge.svg?bg=632CA6)](https://chat.datadoghq.com/)
 [![License](https://img.shields.io/badge/license-Apache--2.0-blue)](https://github.com/DataDog/datadog-lambda-python/blob/main/LICENSE)
 
 Datadog Lambda Library for Python (2.7, 3.6, 3.7 and 3.8) enables enhanced Lambda metrics, distributed tracing, and custom metric submission from AWS Lambda functions.  
@@ -99,6 +99,10 @@ You can also open an issue for a feature request.
 
 If you find an issue with this package and have a fix, please feel free to open a pull request following the [procedures](CONTRIBUTING.md).
 
+## Community
+
+For product feedback and questions, join the `#serverless` channel in the [Datadog community on Slack](https://chat.datadoghq.com/).
+
 ## License
 
 Unless explicitly stated otherwise all files in this repository are licensed under the Apache License Version 2.0.