build(desktop): improve desktop build process, update assets

resources/readme.md

@@ -0,0 +1,29 @@
+# Copay Project Resources
+
+This directory contains a `src.sketch` file from which all other assets are exported or derived.
+
+## Requirements
+
+You'll need [Sketch](https://www.sketchapp.com/) to make any changes to this directory.
+
+Sketch is only available for macOS, and several processes in `generate.sh` require utilities that ship with the OS, so this process must be performed on macOS.
+
+## Install sketchtool
+
+If you do not have `sketchtool` installed, you'll first need to install it.
+
+```sh
+install.sh
+```
+
+## Generate assets
+
+To make an update, first make the change in `src.sketch`, then run:
+
+```sh
+sh generate.sh
+```
+
+## Commit the changes
+
+Be sure to commit the modified `src.sketch`, as well as any modified exported assets.