chore: add doc for cli testing in olake-ui

docs/community/setting-up-a-dev-env.mdx

@@ -835,5 +835,68 @@ Now, set up debug points in the codebase and click "Launch Go Code".
 
 ## 7. OLake UI Setup
 
-**UI setup**: Please follow the setup instructions at [https://github.com/datazip-inc/olake-ui/](https://github.com/datazip-inc/olake-ui/)
+**UI setup**: Please follow the setup instructions at [Quick Start (Docker Compose)](https://olake.io/docs/getting-started/quickstart/#quick-start-docker-compose)
 
+### Local Testing with Custom Drivers
+
+This guide explains how to test changes made in the [olake-cli](https://github.com/datazip-inc/olake) repository within the [olake-ui](https://github.com/datazip-inc/olake-ui) environment. This is useful for testing new features, or JSON schema changes
+
+#### 1. Build Custom Images
+
+Before running the tests, build custom Docker images for the driver under test.
+
+Execute the following commands from the root of the [olake-cli](https://github.com/datazip-inc/olake) repository on your current working branch.
+Build the image for the desired source driver and also build the MySQL image, as MySQL is used as the default driver for destination-related operations.
+
+Before building the images, make sure the JAR file exists:
+
+```bash
+mvn -f destination/iceberg/olake-iceberg-java-writer/pom.xml clean package -DskipTests
+```
+
+```bash
+# Build source image for the selected driver
+docker build \
+  --build-arg DRIVER_NAME=<driver_name> \
+  -t olakego/source-<driver_name>:<version_tag> \
+  .
+```
+
+```bash
+# Build image for MySQL (required for destination related operations)
+docker build \
+  --build-arg DRIVER_NAME=mysql \
+  -t olakego/source-mysql:<version_tag> \
+  .
+```
+
+
+#### 2. Configure Environment Variables
+
+The UI server needs to be informed to use these custom images and bypass the standard version compatibility checks.
+
+Set the following environment variables to the `olake-ui` service in the `docker-compose-v1.yml` file:
+
+| Variable | Value | Description |
+| :--- | :--- | :--- |
+| `APP_ENV` | `development` | Enables developement environment. |
+| `CUSTOM_DRIVER_VERSION` | `<version_tag>` | The specific tag you used when building your custom image. |
+
+#### Docker compose:
+```bash title="docker-compose-v1.yml"
+olake-ui:
+    image: ${CONTAINER_REGISTRY_BASE:-registry-1.docker.io}/olakego/ui:latest
+    pull_policy: always
+    container_name: olake-ui
+    environment:
+        APP_ENV: development
+        CUSTOM_DRIVER_VERSION: <version_tag>
+```
+
+#### 3. How It Works
+
+`CUSTOM_DRIVER_VERSION` takes effect only when `APP_ENV` is set to `development`.
+
+When both are set:
+- The specified version is added to the driver version dropdown in the UI.
+- Semver compatibility checks are bypassed.