chore: add GitPod configuration (#29)

.gitpod.yml

@@ -0,0 +1,11 @@
+github:
+  prebuilds:
+    pullRequestsFromForks: true
+
+vscode:
+  extensions:
+    - ms-vscode.makefile-tools
+
+tasks:
+  - before: pip install -U pip pipenv
+    init: pipenv sync --dev --pre

CONTRIBUTING.md

@@ -15,7 +15,7 @@ If it is not, [create a bug report](https://github.com/Kosmorro/lib/issues/new/c
 Have an idea of feature you think would be nice on Kosmorro? Time to suggest it!
 First, please check someone didn't suggest your next revolution in the _Issues_ tab. If it's not, [create a feature request](https://github.com/Deuchnord/kosmorro/issues/new/choose) and fill in the templace that offers to you.
 
-## Writing code
+## Writing code [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/Kosmorro/lib)
 
 First of all, if you are fixing an opened issue, check that nobody is already working on it — if someone seems to be but their Pull Request seems stuck, please ask them first if you can continue the development. If you retake the code they produced, **don't change the author of the commits**.