refactor: added how to release md

HOW_TO_RELEASE.md

+# How To Release ?
+
+This one is mainly for [me](@jerome_etienne) to remember :)
+
+```bash
+# Update CHANGELOG.md - remove the -dev into version
+atom CHANGELOG.md
+
+# replace REVISION to the proper version, search/replace on the version string should do it
+atom three.js/src/threex/threex-artoolkitcontext.js package.json README.md
+
+# Rebuild and minify everything - aka a-frame and three.js
+make minify
+
+# Commit everything
+git add . && git commit -a -m 'Last commit before release' && git push
+
+# Go to master branch
+git checkout master
+
+# Merge dev branch into master branch
+git merge dev
+
+# tag the release
+git tag 1.5.5
+
+# push the tag on github
+git push origin --tags
+
+# push commits tag on github
+git push
+
+# update npm package.json
+npm publish
+
+# Come back to dev branch
+git checkout dev
+
+# Update CHANGELOG.md - start new dev version
+atom CHANGELOG.md
+
+# update the a-frame codepen if needed
+open "https://codepen.io/jeromeetienne/pen/mRqqzb?editors=1000#0"
+```