chore: Added Deploy To Digital Ocean Button (#874)

Co-authored-by: Ivar Conradi Østhus <[email protected]>

.do/deploy.template.yaml

@@ -0,0 +1,8 @@
+spec:
+  services:
+  - name: unleash-server
+    git:
+      branch: master
+      repo_clone_url: https://github.com/Unleash/unleash.git
+  databases:
+  - name: unleash-db

README.md

@@ -1,6 +1,6 @@
 <div align="center">
 
-![Build & Tests](https://github.com/Unleash/unleash/workflows/Build%20%26%20Tests/badge.svg?branch=master) [![Coverage Status](https://coveralls.io/repos/github/Unleash/unleash/badge.svg?branch=master)](https://coveralls.io/github/Unleash/unleash?branch=master) [![Deploy](./.github/deploy-heroku-20.png)](https://www.heroku.com/deploy/?template=https://github.com/Unleash/unleash) [![npm](https://img.shields.io/npm/v/unleash-server)](https://www.npmjs.com/package/unleash-server) [![Docker Pulls](https://img.shields.io/docker/pulls/unleashorg/unleash-server)](https://hub.docker.com/r/unleashorg/unleash-server)
+![Build & Tests](https://github.com/Unleash/unleash/workflows/Build%20%26%20Tests/badge.svg?branch=master) [![Coverage Status](https://coveralls.io/repos/github/Unleash/unleash/badge.svg?branch=master)](https://coveralls.io/github/Unleash/unleash?branch=master) [![Deploy](./.github/deploy-heroku-20.png)](https://www.heroku.com/deploy/?template=https://github.com/Unleash/unleash)[![Deploy to DO](./.github/deploy-digital.svg)](https://cloud.digitalocean.com/apps/new?repo=https://github.com/Unleash/unleash/tree/master) [![npm](https://img.shields.io/npm/v/unleash-server)](https://www.npmjs.com/package/unleash-server) [![Docker Pulls](https://img.shields.io/docker/pulls/unleashorg/unleash-server)](https://hub.docker.com/r/unleashorg/unleash-server)
 
 <a href="https://getunleash.io" title="Unleash - Create with freedom. Release with confidence">
     <img src="./.github/Logo_DarkBlue_Transparent_Portrait.svg" width="200">