Dev.md: guidelines (PR #1133)

An attempt to a few important things to newcomers, to reduce the risk
of contributors being disappointed / contradicted late at PR time.

docs/development.md

@@ -1,5 +1,25 @@
 # Development Guide
 
+Welcome, soon-to-be contributor 🙂! This document sums up what you
+need to know to get started hacking on Nativefier.
+
+## Guidelines
+
+1. Before starting work on a huge change, gauge the interest
+   of community & maintainers through a GitHub issue.
+   For big changes, create a [RFC])(https://en.wikipedia.org/wiki/Request_for_Comments)
+   issue to enable a good peer review.
+2. Do your best to avoid adding new Nativefier command-line options.
+   If a new option is inevitable for what you want to do, sure,
+   but as much as possible try to see if you change works without.
+   Nativefier already has a ton of them, making it hard to use.
+3. Avoid or limit adding npm dependencies.
+   Each new dependency is a complexity & security liability.
+4. Use types, avoid `any`, write tests. In that order.
+5. Document for users in API.md
+6. Document for other devs in comments, jsdoc, commits, PRs.
+   Say *why* more than *what*, the *what* is your code!
+
 ## Setup
 
 First, clone the project: