Add custom-select class to select element

app/dashboard/templates/dashboard/custom_alias.html

@@ -40,7 +40,7 @@
 
 
         <div class="col-sm-6 p-1">
-          <select class="form-control" name="suffix">
+          <select class="form-control custom-select" name="suffix">
             {% for suffix in suffixes %}
               <option value="{{ suffix[1] }}">
                 {% if suffix[0] %}
@@ -57,7 +57,7 @@
       {% if mailboxes|length > 1 or current_user.full_mailbox %}
         <div class="row mb-2">
           <div class="col p-1">
-            <select class="form-control" name="mailbox">
+            <select class="form-control custom-select" name="mailbox">
               {% for mailbox in mailboxes %}
                 <option value="{{ mailbox }}">
                   {{ mailbox }}

app/oauth/templates/oauth/authorize.html

@@ -106,7 +106,7 @@
 
                 <div class="col-sm-6"
                      style="padding-left: 5px">
-                  <select class="form-control" name="suffix">
+                  <select class="form-control custom-select" name="suffix">
                     {% for suffix in suffixes %}
                       <option value="{{ suffix[1] }}">
                         {% if suffix[0] %}