Add gitpod integration

.gitpod.Dockerfile

+FROM gitpod/workspace-full
+
+RUN sudo apt-get update && \
+    sudo apt-get install -y zsh && \
+    sudo rm -rf /var/lib/apt/lists/*

.gitpod.yml

+image:
+  file: .gitpod.Dockerfile
+
+tasks:
+  - init: |
+      export EDITOR="command gp open -w" VISUAL="command gp open -w"
+      cp -f /workspace/ohmyzsh/templates/zshrc.zsh-template ~/.zshrc
+      ln -sf /workspace/ohmyzsh ~/.oh-my-zsh
+    command: exec zsh

README.md

@@ -15,6 +15,7 @@ To learn more, visit [ohmyz.sh](https://ohmyz.sh), follow [@ohmyzsh](https://twi
 [![CI](https://github.com/ohmyzsh/ohmyzsh/workflows/CI/badge.svg)](https://github.com/ohmyzsh/ohmyzsh/actions?query=workflow%3ACI)
 [![Follow @ohmyzsh](https://img.shields.io/twitter/follow/ohmyzsh?label=Follow+@ohmyzsh&style=flat)](https://twitter.com/intent/follow?screen_name=ohmyzsh)
 [![Discord server](https://img.shields.io/discord/642496866407284746)](https://discord.gg/ohmyzsh)
+[![Gitpod ready](https://img.shields.io/badge/Gitpod-ready-blue?logo=gitpod)](https://gitpod.io/#https://github.com/ohmyzsh/ohmyzsh)
 
 ## Getting Started