docs: update build instructions to use asdf for tool management

- Add asdf prerequisites and installation steps to README.md
- Document development workflow with asdf in CONTRIBUTING.md
- Replace JDK 8 requirement with asdf-managed versions
- Include verification commands for tool installation
- Add step-by-step development workflow for contributors

This aligns documentation with the new asdf-based CI/CD workflows
and provides clear setup instructions for new contributors.

Author: aravind666

CONTRIBUTING.md

@@ -1,7 +1,32 @@
 # Contributing
 
 This project welcomes contributions and suggestions. 
-When you submit a pull request, we have checks which run on your PR for standards that we expect .
+When you submit a pull request, we have checks which run on your PR for standards that we expect.
+
+## Prerequisites
+
+Before contributing, ensure you have the following installed:
+
+1. **asdf** - Tool version manager
+   - Installation guide: https://asdf-vm.com/guide/getting-started.html
+   - Install required plugins:
+     ```bash
+     asdf plugin add java
+     asdf plugin add gradle
+     ```
+
+2. **Install project tools**
+   - Navigate to the project directory and run:
+     ```bash
+     asdf install
+     ```
+   - This will install the Java and Gradle versions specified in `.tool-versions`
+
+3. **Verify installation**
+   ```bash
+   java -version
+   gradle -version
+   ```
 
 ## Code of Conduct
 
@@ -37,6 +62,28 @@ Check out the links below to get started.
 - Be prepared to discuss a feature and take feedback.
 - Include unit tests and updates documentation to complement the change.
 
+### Development workflow
+
+1. **Set up your environment**
+   ```bash
+   asdf install  # Install Java and Gradle from .tool-versions
+   ```
+
+2. **Run quality checks locally**
+   ```bash
+   ./gradlew clean build pitest shadowJar
+   ```
+   This runs all quality gates including tests, PMD, CPD, Checkstyle, code coverage, and mutation testing.
+
+3. **Make your changes**
+   - Follow the existing code style and conventions
+   - Ensure all quality checks pass before submitting a PR
+
+4. **Submit a pull request**
+   - Target the `main` branch
+   - Ensure CI workflows pass on your PR
+   - Address any review feedback promptly
+
 [learn-git]: https://help.github.com/en/articles/git-and-github-learning-resources
 [github-flow]: https://guides.github.com/introduction/flow/
 [github-signup]: https://github.com/signup/free

README.md

@@ -23,14 +23,27 @@ We asked ourselves the same question! Why create a new tool when there were many
 
 ## How to use Ceberus? 
 ### Build Cerberus from source
-To build Cerberus, you will need a JDK 8 installed in your system. 
-The final output of build is an executable JAR. We have created gradle tasks to achieve the same, review our build.gradle file for more details.  
+Cerberus uses [asdf](https://asdf-vm.com/) for managing Java and Gradle versions. The required tool versions are specified in the `.tool-versions` file.
 
+**Prerequisites:**
+- Install [asdf](https://asdf-vm.com/guide/getting-started.html)
+- Install asdf plugins: `asdf plugin add java` and `asdf plugin add gradle`
+
+**Build Steps:**
 1. Clone the repository
-`git clone https://github.com/philips-software/cerberus.git`
-2. Build it using the following command
-`./gradlew clean build shadowJar`
-The executable jar will be generated in the build/libs folder. 
+   ```bash
+   git clone https://github.com/philips-software/cerberus.git
+   cd cerberus
+   ```
+2. Install tools from .tool-versions
+   ```bash
+   asdf install
+   ```
+3. Build the executable JAR
+   ```bash
+   ./gradlew clean build shadowJar
+   ```
+   The executable jar will be generated in the build/libs folder. 
 
 ### Run Cerberus as a command line tool
 Once the jar gets generated,  use the jar to run Cerberus