Alias for Ionic environment variables

[gshigeto]

Short description of what this resolves:

Enables environment variables for any IONIC_ENV

Changes proposed in this pull request:

• Create an alias @app/env for users to import their environment variables

Fixes: #762

Second half of this implementation in pull request for ionic2-app-base

[gshigeto]

The second half of this implementation in pull request for ionic2-app-base

[janpio]

Oh wow, this looks neat!

Is there some documentation on how this would be used somewhere?
Was this presented and explained in #762?

[gshigeto]

Thank you!

I am sorry as this is my first PR for an open source project and don't know proper protocol.

I commented on a thread for environment variables here.
Here is the link to my sample repo that I made for it.

[janpio]

I think you might also want to post in #762 with a short summary how it works and how you would use this in the project when merged.

[tabirkeland]

Utilizing this currently in a project, had to resolve issues for both custom webpack.config.js and optimization.config.js, see below:

var path = require('path');
var defaultConfig = require('@ionic/app-scripts/config/webpack.config.js');

module.exports = function () {
	const alias = {
		"@app/env" : path.resolve('./src/environments/environment.ts')
	};
	defaultConfig.dev.resolve.alias = alias;
	defaultConfig.prod.resolve.alias = alias;

	return defaultConfig;
};