register firefox fix

src/app/components/register/register.component.html

@@ -1,10 +1,10 @@
 <div class="card">
-  <div class="well">
+  <div class="well d-flex flex-column justify-content-center">
     <p class="h5 text-center mb-4">Sign up</p>
     <p class="text-center mb-4" style="padding-top: 2%;">Êtes-vous <strong>Parrain</strong> ou <strong>Commercant</strong> ?</p>
 
     <label>
-      <form class="form-inline">
+      <form class="form-inline d-flex flex-row justify-content-center">
         <div class="md-form" style="padding-left: 2%;">
           <input name="group2" type="radio" class="with-gap" id="parrain"  (click)="ngOnDestroy()" value="Parrain" [(ngModel)]="currentUser.status">
           <label for="parrain">Parrain</label>