Support using clasp CLI to update apps script project

[simonkotwicz]

I'm not sure what the current suggested way to update your own apps script project is (perhaps running uninstall on the current project, copying a new project, adding back customizations and then running install... or maybe just copying and pasting files?). I think maybe there should be a spot in the comments or README that specifies this. I don't mind making a PR to that effect.

However, in general I think it's easier to easier to pull down new releases/changes from github and push them to Google apps script with the clasp CLI. One of the issues with this right now is that when you pull down changes from a google apps script project it renames files with a .gs extension to use .js locally (and therefore creates a duplicate of each file with a different extension). So I was wondering if it might make sense to rename .gs files with the .js extension in this repo.

Another thing to make updates a bit cleaner would be to separate out the config section into its own file.

... So 3 proposed changes:

1. Add update instructions (assuming they're not already somewhere)
2. Rename .gs files to use .js
3. Externalize personal config to a config.js or config.json file

[artmg]

The issue where claps push renames files clasp issue #51 has now been fixed. As of 2.4.2 the behaviour is definitely to leave the .gs extension when pushing local files into script files.
Only 1. and 3. would be required.

[artmg]

Item 3. has been delivered via branch local-settings of my fork:

• for instructions see https://github.com/artmg/GAS-ICS-Sync/blob/local-settings/use_local_settings_file.md
• and check out the _LocalSettings.gs file to see how straightforward it is

I have kept this separate in case anyone from the main project might be interested. Now I will work on a branch to address and document 1.

[jonas0b1011001]

I added clasp instructions to an upcoming release https://github.com/derekantrican/GAS-ICS-Sync/blob/settings-v2/About.gs, feel free to comment on it as i don't use this setup personally.

[artmg]

Thanks for including those, I reckon they should be clear enough for anyone who is advanced enough to want to try clasp.

Thanks also for your efforts to rationalise and improve the project structure, I hope that the community gets the hang of it quickly, as it looks more logical to me - well done