Update contributing

Author: nojaf

CONTRIBUTING.md

@@ -32,7 +32,11 @@ git clone --depth 1 https://github.com/rescript-lang/rescript-compiler.git
 
 This will only consume less than 50MB.
 
-## Install OCaml compiler + dependencies
+## Installation
+
+### A. Manual installation
+
+#### Install OCaml compiler + dependencies
 
 The ReScript compiler compiles with any recent OCaml compiler. We are using `dune` as a build system for easy workflows and proper IDE support.
 
@@ -51,10 +55,18 @@ opam install . --deps-only
 opam install ocaml-lsp-server
 ```
 
-## npm install
+#### npm install
 
 Run `npm install --ignore-scripts`. This will install the npm dependencies required for the build scripts.
 
+### B. Devcontainer
+
+The repository additionally provides [development container](https://containers.dev/) definition that can be used with [VSCode's Remote Containers extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers) - use it to get stable development environment.
+
+Run the `Dev Containers: Rebuild and Reopen in Container` action to get started.
+
+You can also open this dev container with [GitHub Codespaces](https://github.com/features/codespaces/).
+
 ## Building the Compiler
 
 The compiler binaries themselves can be built directly with dune as follows: