Adds functionality to make ng2-select compatible with form-controls

[sonukapoor]

Please review attached PR. It allows you to use the ng2-select component with ngModel.

Simple usage:

Add the following attributes:

name is the name of your control.
[(ngModel)] should be set to your selected items. It's should be the same as [active].

`<form #form="ngForm">
<ng-select required
name="mySelect"
#mySelect="ngModel"
[(ngModel)]="selectedItems"
[active]="selectedItems"
[items]="newItems">

`

Is Form Valid: {{ form.valid }}

Is Control Valid: {{ mySelect.valid }}

Note: I have tested this only with template forms.

Feedback is appreciated.

[codecov]

Codecov Report

Merging #881 into development will decrease coverage by 6.95%.
The diff coverage is 55.81%.

@@               Coverage Diff               @@
##           development     #881      +/-   ##
===============================================
- Coverage        37.33%   30.37%   -6.96%     
===============================================
  Files               11       11              
  Lines              450      451       +1     
  Branches            73       76       +3     
===============================================
- Hits               168      137      -31     
- Misses             282      313      +31     
- Partials             0        1       +1

Impacted Files	Coverage Δ
src/select/select.ts	19.04% <55.81%> (-8.67%)	⬇️
src/select/select-pipes.ts	31.57% <0%> (-3.43%)	⬇️
src/select/off-click.ts	70% <0%> (-2.73%)	⬇️
src/select/select.module.ts	100% <0%> (ø)	⬆️

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[sonukapoor]

@valorkin Any chance to get this merged?

[eamonn]

@sonukapoor good work. Any chance you can merge this @valorkin ???

[valorkin]

thanks for contributing!
please remove package-lock

I am addressing this PR to ngx team, we will try to publish it soon

[sonukapoor]

Will do.

…

On Wed, Oct 25, 2017 at 8:01 AM Dmitriy Shekhovtsov < ***@***.***> wrote: thanks for contributing! please remove package-lock I am addressing this PR to ngx team, we will try to publish it soon — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#881 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AADpVrw8RhRGNfVs7UZLD2dOtNeI_N-kks5svyMTgaJpZM4POtb3> .

[sonukapoor]

@valorkin done. I also reverted the other files. Please also note that my vs code formatted the file with proper spaces etc. and when reviewing you should ignore the white spaces:

https://github.com/valor-software/ng2-select/pull/881/files?w=1

[mohamedfathii]

when this PR will be merged ?

[sonukapoor]

I have a separate fork with the compiled version of the ng2-select using this PR that is available for anybody that wants to use it:

https://github.com/sonukapoor/ng2-select-forms

[IlyaSurmay]

I'm updating dependencies right now so we'll be able to test it soon, then it will be merged.