implement Double-Opt-In

CRM/Twingle/Form/Profile.php

@@ -336,6 +336,13 @@ class CRM_Twingle_Form_Profile extends CRM_Core_Form {
       array('class' => 'crm-select2 huge', 'multiple' => 'multiple')
     );
 
+    $this->add(
+       'checkbox', // field type
+       'double_opt_in', // field name
+       E::ts('Use Twingle\'s Double-Opt-In procedure'), // field label
+       FALSE // is not required
+     );
+
     $this->add(
       'select', // field type
       'postinfo_groups', // field name

CRM/Twingle/Profile.php

@@ -221,6 +221,7 @@ class CRM_Twingle_Profile {
         'membership_type_id',
         'membership_type_id_recur',
         'membership_postprocess_call',
+        'double_opt_in'
       ),
       // Add payment methods.
       array_keys(static::paymentInstruments()),
@@ -293,6 +294,7 @@ class CRM_Twingle_Profile {
       'custom_field_mapping' => NULL,
       'membership_type_id' => NULL,
       'membership_type_id_recur' => NULL,
+      'double_opt_in' => NULL,
     )
       // Add contribution status for all payment methods.
       + array_fill_keys(array_map(function($attribute) {