Improve deploying to GHPages

[affilnost]

What we have now

We have now script to deploy the project to "Github Pages":
npm run deploy-to-ghpages
See more at https://github.com/angular-schule/angular-cli-ghpages

What we need

What we need now is to be able to deploy only the last release (the last release tag).
For example, it would be nice to specify the commit hash to deploy, something like this:
npm run deploy-to-ghpages -commit [commit_hash]
or to specify the app version to deploy, like this:
npm run deploy-to-ghpages -version [version_number]
Or maybe just to deploy somehow always the last version. It depends on what will be easier to make.

The main goal is that no "unreleased" version is going to be deployed.

Also the README.md should be updated accordingly.

[hiteshpr]

I can do this.

[affilnost]

@hiteshpr Sounds great! This issue is reserved for you for now.
If you have any questions, you can write on gitter https://gitter.im/Angular-5-Example-Shopping-App/Lobby
When you're finished, just send a pull-request.

[hiteshpr]

Hi!
I couldn’t find the exact solution.
But, I propose this way -
-- make a gh-pages branch from a particular commit
-- build that branch and deploy it to production/staging.

[affilnost]

@hiteshpr for the moment running:
npm run deploy-to-ghpages
will deploy the current master to production (github).

We need to improve it, for example by taking a particular commit instead of master.
So when running
npm run deploy-to-ghpages -commit [commit_hash]
it will deploy this exact commit.