add basic readme

Signed-off-by: Jakub Sokołowski <jakub@status.im>

README.md

@@ -0,0 +1,47 @@
+# Description
+
+This is a minimal REST API intended for use with a Continuous Integration system for managing comments on GitHub.
+
+The problem this solves is posting comments in a PR from multiple builds without spamming the comment section. Instead we post just one comment with a table and continue to update it.
+
+# Example Comment
+
+---
+| Status | Commit | Build | Duration | Result |
+|-|-|-|-|-|
+| :x: | 5b1b9e9f | [prs/android-e2e/PR-7056#3](https://ci.status.im/job/status-react/job/prs/job/android-e2e/job/PR-7056/3/) | ~6 min | [:page_facing_up: build log](https://ci.status.im/job/status-react/job/prs/job/android-e2e/job/PR-7056/3//consoleText) |
+| :heavy_check_mark: | 5b1b9e9f | [prs/macos/PR-7056#3](https://ci.status.im/job/status-react/job/prs/job/macos/job/PR-7056/3/) | ~13 min | [:package: macos package](https://status-im-prs.ams3.digitaloceanspaces.com/StatusIm-181212-143527-5b1b9e-pr.dmg) |
+---
+
+# API
+
+It exposes just 1 call:
+
+* `PUT /comment/:id` - Post a comment for PR with given ID.
+
+By default it listens on `localhost:8080`.
+
+# Configuration
+
+There are few environment variables you can set:
+
+* `LISTEN_PORT` - Default: `8000`
+
+# Usage
+
+For development use:
+```
+npm run start
+```
+For building use:
+```
+npm run build
+```
+To create the docker image use:
+```
+npm run image
+```
+To push the image use:
+```
+npm run push
+```