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.

Author: viewv

.gitpod.Dockerfile

@@ -0,0 +1,10 @@
+FROM gitpod/workspace-full
+                    
+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

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+tasks:
+  - init: mvn install -DskipTests=false
+image:
+  file: .gitpod.Dockerfile

README.md

@@ -1,3 +1,5 @@
+[![Gitpod Ready-to-Code](https://img.shields.io/badge/Gitpod-Ready--to--Code-blue?logo=gitpod)](https://gitpod.io/#https://github.com/viewv/EncBox) 
+
 # EncBox
 [![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Fviewv%2FEncBox.svg?type=shield)](https://app.fossa.io/projects/git%2Bgithub.com%2Fviewv%2FEncBox?ref=badge_shield)  ![Java CI with Maven](https://github.com/viewv/EncBox/workflows/Java%20CI%20with%20Maven/badge.svg)