Add gitpod config

this commit adds support for Gitpod.io, a free automated
dev environment that makes contributing and generally working on GitHub
projects much easier. It allows anyone to start a ready-to-code dev
environment for any branch, issue and pull request with a single click.

.gitpod.Dockerfile

@@ -0,0 +1,10 @@
+FROM berkus/docker-rusty-ci
+                    
+USER gitpod
+
+# Install custom tools, runtime, etc. using apt-get
+# For example, the command below would install "bastet" - a command line tetris clone:
+#
+# RUN sudo apt-get -q update && #     sudo apt-get install -yq bastet && #     sudo rm -rf /var/lib/apt/lists/*
+#
+# More information: https://www.gitpod.io/docs/config-docker/

.gitpod.yml

@@ -0,0 +1,5 @@
+tasks:
+  - init: cargo build
+    command: cargo watch -x run
+image:
+  file: .gitpod.Dockerfile

README.md

@@ -75,6 +75,10 @@ Based on [Raspi3 tutorials by Andre Richter](https://github.com/rust-embedded/ru
 which are in turn based on [Raspi3 tutorials by bzt](https://github.com/bztsrc/raspi3-tutorial/).
 Various references from [OSDev Wiki](https://wiki.osdev.org/Raspberry_Pi_Bare_Bones) and [RaspberryPi.org manuals](https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf).
 
+----
+
 [![Built with cargo-make](https://sagiegurari.github.io/cargo-make/assets/badges/cargo-make.svg)](https://sagiegurari.github.io/cargo-make)
 
 ![Build](https://github.com/metta-systems/vesper/workflows/Build/badge.svg)
+
+[![Gitpod Ready-to-Code](https://img.shields.io/badge/Gitpod-Ready--to--Code-blue?logo=gitpod)](https://gitpod.io/#https://github.com/metta-systems/vesper)