Add workflow/resource.md [skip ci]

Workflow for changes that touches .resx files
- editing
- updating
- add/remove
- start-resgen

docs/workflow/resources.md

@@ -0,0 +1,31 @@
+# Resources
+
+Resources are `.resx` files with string values that we use for error messages and such.
+They live in `src\<project>\resources` folders.
+
+At the moment `dotnet cli` doesn't support generating C# bindings (strongly typed resource files).
+
+We are using `src\windows-build\gen` folder in [src\windows-build](https://github.com/PowerShell/psl-windows-build) 
+with pre-generated `.cs` files to work-around it.
+See [issue 756](https://github.com/PowerShell/PowerShell/issues/746) for details.
+
+## Editing resx files
+
+**Don't edit** resx files from Visual Studio. 
+It will try to create `.cs` files for you and you will get whole bunch of hard-to-understand errors.
+
+To edit resource file, use any **plain text editor**. 
+Resource file is a simple xml, and it's easy to edit.
+
+### Updating string
+
+If you just updated the string value, that's all you need to do: no need to re-generate `.cs` files
+
+### Adding or removing string
+
+When you adding or removing string, `.cs` file need to be changed.
+
+1. Run `Start-ResGen` function from `PowerShellGitHubDev.psm1`
+1. Make sure your code is building with newly generated resources (run `Start-PSBuild`).
+1. Go to submodule (`cd src\windows-build`) and perform the [submodule commit dance](docs/git/committing.md).
+Follow working with [submodule rules](CONTRIBUTING.md#submodules)