Add a contributing file with technical basics

CONTRIBUTING.md

@@ -1,23 +1,43 @@
 # CONTRIBUTING
 
-## Technical Notes
+This page provides some general technical information about concepts and
+tools used in this project. We hope this
+will help guide future contributors to
+helpful resources.
 
-bindings
+## What is a binding
 
-ZMQ C/C++
+A binding makes it easier for a Node.js application to take advantage of the
+[ZMQ C++ library](https://github.com/zeromq/libzmq), `libzmq`. The binding
+provides native JavaScript support to use the ZMQ library.
 
-Node.js usage
+## What is `libzmq`
 
-We create a binding to make it easier to use the C/C++ code.
+[Libzmq](https://github.com/zeromq/libzmq) is the low-level library behind
+most of the different language bindings, including `zeromq.js`. Libzmq exposes
+a C-API and is implemented in C++.
 
-[node-gyp - Node.js native addon build tool](https://www.npmjs.com/package/node-gyp)
-- node-gyp is a cross-platform command-line tool written in Node.js for compiling native addon modules for Node.js.
+## How to create the binding
+
+To create the binding, use [`node-gyp` Node.js native addon build tool](https://www.npmjs.com/package/node-gyp). `node-gyp` is a cross-platform command-line tool
+written in Node.js for compiling native addon modules for Node.js.
 - `npm install -g node-gyp` to install
 - `node-gyp configure`
 - `node-gyp build`
 - For a debug build add `--debug` to the configure and build commands
-- A `binding.gyp` file describes the configuration to build your module, in a JSON-like format. This file gets placed
-  in the root of your package, alongside `package.json`.
+
+## What is a `binding.gyp` file
+
+A `binding.gyp` file describes the configuration to build your module. This file
+gets placed in the root of your package, alongside `package.json`.
+
+[GYP](https://gyp.gsrc.io/index.md), short for Generate Your Project, is a build
+tool similar to Cmake. GYP was originally created to generate native IDE project
+files (Visual Studio, Xcode) for building Chromium.
+
+The `.gyp` file is structured as a Python dictionary.
+
+## Weak-napi
 
 https://www.npmjs.com/package/weak-napi
 On certain rarer occasions, you run into the need to be notified when a JavaScript object is going to be garbage collected. This feature is exposed to V8's C++ API, but not to JavaScript.