Platform: docs: Create community section

[brandonroberts]

Other information:

I would be willing to submit a PR for the docs :heart:

[ ] Yes (Assistance is provided if you need help submitting a pull request)
[ ] No

We have an awesome community of people creating great content, libraries, and talks. We need a place to promote and provide visibility.

[timdeschryver]

I should be able to get this one started if that would be OK.
I was thinking of adding a menu item in the header, between docs and GitHub.

[brandonroberts]

👍

[LMFinney]

A co-worker and I created this library to use Java-style enums to defined actions: ngrx-enums

[DenysVuika]

We have recently started using NgRx in production for this Angular 6 application: Alfresco Content App and are extremely happy with the results. All NgRx-related stuff can be found here.

[ngohungphuc]

I have one small app using ASP.Net Core 2.0 and Angular 4 with Ngrx. Demo can be found here
Source code: https://github.com/ngohungphuc/online-training

Second app is small sample login app using angular 6 and ngrx
Source code: https://github.com/ngohungphuc/Research/tree/master/Angular/Redux/ReduxDemo

[timdeschryver]

Resources are added at https://github.com/ngrx/platform/pull/1418