ngx-formly: FlexLayout in Angular Material (elementAttributes is not effecting)

[x] bug report 

[ x ] support request

Current behavior

Expected behavior

Minimal reproduction of the problem with instructions

Followed this URL to build this but here it is bootstrap but am trying with material

http://angular-formly.com/#!/example/integrations/angular-material

# Code Html File

 <form [formGroup]="form" (ngSubmit)="submit(model)">
    <formly-form [form]="form" [fields]="fields" [model]="model" >
      <button type="submit" class="btn btn-default">Submit</button>
    </formly-form>
  </form>

TypeScript File

form = new FormGroup({});
 model = { email: 'email@gmail.com' };
 fields = [{
   'key': 'text',
   'type': 'input',
   className: 'flex',
   'templateOptions': {
     'label': 'Input',
   }
 },
 {
   elementAttributes: {
     layout: 'column',
     fieldGroupClassName: 'flex flex-50'
   },
   'fieldGroup': [
     {
       'key': 'firstName',
       className: 'flex',
       'type': 'input',
       'templateOptions': {
         'label': 'First Name',
       }
     },
     {
       'key': 'lastName',
       className: 'flex',
       'type': 'input',
       'templateOptions': {
         'label': 'Last Name'
       }
     }
   ]
 },
 {
   'key': 'knowsMuffinMan',
   'type': 'checkbox',
   'templateOptions': {
     'label': 'Do you know the muffin man?'
   }
 }
 ];

App.Module. file

import {ReactiveFormsModule, FormsModule} from '@angular/forms';
import {FormlyModule} from '@ngx-formly/core';
import { AppComponent } from './app.component';
import {FormlyMaterialModule} from '@ngx-formly/material';
import {FlexLayoutModule} from '@angular/flex-layout';

What is the motivation / use case for changing the behavior? dynamically display Side by side columns in row ,from JSON file usin flex layout

Please tell us about your environment:

• Angular version: ^5.0.0

• Angular Formly/Material: “^2.0.0-rc.50”

• Browser: [all | Chrome Version 65.0.3325.181

• Language: [all | “typescript”: “~2.4.2” | ES6/7 | ES5]

• Node (for AoT issues): node --version = 8.9.1