Create ONBOARDING.md (#836)

* Create ONBOARDING.md

* refactor: fixing formatting

Author: anandtiwary

ONBOARDING.md

@@ -0,0 +1,34 @@
+# UI Onboarding
+
+This documents contains the onboarding guide for hypertrace-ui.
+
+- [Fork the repository](https://docs.github.com/en/github/getting-started-with-github/fork-a-repo)
+- Tools Setup:
+  - [Node and Npm](https://www.npmjs.com/get-npm)
+- Techologies Used
+  1.  [Angular](https://angular.io/docs)
+  2.  [Typescript 4.x](https://www.typescriptlang.org/docs/)
+  3.  [Angular Testing with Spectator](https://github.com/ngneat/spectator)
+      - Policy around testing.
+        - Unit tests: Component test and service test
+        - Shallow test
+      - CodeCov requirements
+      - Tools used:
+        Jest, vscode-jest and wallabyjs
+  4.  [Rxjs](https://rxjs.dev/guide/overview/)
+  5.  [D3Js](https://github.com/d3/d3/wiki)
+- Libraries Used
+
+  - [Hyperdash](https://github.com/hypertrace/hyperdash/blob/main/README.md)
+  - [Hyperdash angular](https://github.com/hypertrace/hyperdash-angular/blob/main/README.md)
+  - [Assets-Library](https://github.com/hypertrace/hypertrace-ui/tree/main/projects/assets-library)
+  - [Common](https://github.com/hypertrace/hypertrace-ui/tree/main/projects/common)
+  - [Components](https://github.com/hypertrace/hypertrace-ui/tree/main/projects/components)
+  - [Dashboards](https://github.com/hypertrace/hypertrace-ui/tree/main/projects/dashboards)
+  - [Distributed Tracing](https://github.com/hypertrace/hypertrace-ui/tree/main/projects/distributed-tracing)
+  - [Observability](https://github.com/hypertrace/hypertrace-ui/tree/main/projects/observability)
+
+- [Hypertrace ui app](https://github.com/hypertrace/hypertrace-ui/tree/main/src)
+- Hyperdash and writing config driven UI
+
+[^1]: More to be added soon.