adding developer guide to reference from source.html on the project w…

…ebsite and because we should have one to encourage contributions

Signed-off-by: Mark Cohen <[email protected]>

DEVELOPER_GUIDE.md

@@ -0,0 +1,45 @@
+## Developer Guide
+
+So you want to contribute code to this project? Excellent! We're glad you're here. Here's what you need to do.
+
+### Setup
+
+1. Git clone OpenSearch-Dashboard for the version that matches the version you want to use [OpenSearch-Dashboards](https://github.com/opensearch-project/OpenSearch-Dashboards)
+2. Change your node version to the version specified in `.node-version` inside the OpenSearch Dashboards root directory. (using [nvm](https://github.com/nvm-sh/nvm) can help for that)
+3. Change directory into `OpenSearch-Dashboards` and git clone [dashboards-search-relevance](https://github.com/opensearch-project/dashboards-search-relevance) into the `plugins/` directory.
+4. Run `yarn osd bootstrap` inside `OpenSearch-Dashboards`.
+
+Ultimately, your directory structure should look like this:
+
+```md
+.
+├── OpenSearch-Dashboards
+│   └── plugins
+│       └── dashboards-search-relevance
+```
+
+### Build
+
+To build the plugin's distributable zip simply run `yarn build`.
+
+The output file : `./build/searchRelevanceDashboards-?.?.?.zip` (`?.?.?` stands for the version number)
+
+### Run Directly
+
+Cd back to `OpenSearch-Dashboards` directory and run `yarn start` to start OpenSearch Dashboards including this plugin. OpenSearch Dashboards will be available on `localhost:5601`.
+
+### Run Docker
+
+Run `docker-compose up -d` after changing the [Dockerfile](Dockerfile) as described in this [tutorial](Using-Docker.md)
+
+### Submitting Changes
+
+See [CONTRIBUTING](CONTRIBUTING.md).
+
+### Backports
+
+The Github workflow in [`backport.yml`](.github/workflows/backport.yml) creates backport PRs automatically when the original PR
+with an appropriate label `backport <backport-branch-name>` is merged to main with the backport workflow run successfully on the
+PR. For example, if a PR on main needs to be backported to `1.x` branch, add a label `backport 1.x` to the PR and make sure the
+backport workflow runs on the PR along with other checks. Once this PR is merged to main, the workflow will create a backport PR
+to the `1.x` branch.