Linking custom table to user table

<field key="supplier" dbtype="int" precision="1" phptype="integer" null="true"/>
<field key="supplieragent" dbtype="int" precision="1" phptype="integer" null="true"/>

<index alias="userdata_id" name="userdata_id" primary="false" unique="true" type="BTREE">

<div class="x-form-item x-tab-item">
    <label class="x-form-item-label" style="width:auto; font-weight:bold; float:none; font-size:12px">Supplier</label>

    <div class="x-form-item x-tab-item">
        <input type="checkbox" name="supplier" value="[[+supplier]]" class="x-form-text x-form-field"
                onClick="Ext.getCmp('modx-panel-user').markDirty();"/>
    </div>

</div>

<div class="x-form-item x-tab-item">
    <label class="x-form-item-label" style="width:auto; font-weight:bold; float:none; font-size:12px">Supplier Agent</label>

    <div class="x-form-item x-tab-item">
        <input type="checkbox" name="supplieragent" value="[[+supplieragent]]" class="x-form-text x-form-field"
                onClick="Ext.getCmp('modx-panel-user').markDirty();"/>
    </div>

</div>

<p>[[!Register? 
&submitVar=`registerbtn` 
&activationResourceId=`16` 
&activationEmailTpl=`tblRegistrationEmail` 
&activationEmailSubject=`Thanks for Registering!` 
&usergroups=`suppliers` 
&validate=`nospam:blank, username:required:minLength=^6^, password:required:minLength=^6^, password_confirm:password_confirm=^password^, fullname:required, email:required:email,company:required:minLength=^3^`
&placeholderPrefix=`reg.` ]]</p>

<div class="register">
  <div class="registerMessage">[[!+reg.error.message]]</div>
  
  <form class="form" action="[[~[[*id]]]]" method="post">
  
	<input type="hidden" name="nospam" value="[[!+reg.nospam]]" />
	
	<label for="username">[[%register.username? &namespace=`login` &topic=`register`]]<span class="error">[[!+reg.error.username]]</span></label> 
	<input id="username" type="text" name="username" value="[[!+reg.username]]" /><br>

	
	<label for="password">[[%register.password]]<span class="error">[[!+reg.error.password]]</span></label> 
	<input id="password" type="password" name="password" value="[[!+reg.password]]" /> <br>
	
	
	<label for="password_confirm">[[%register.password_confirm]]<span class="error">[[!+reg.error.password_confirm]]</span></label>
	<input id="password_confirm" type="password" name="password_confirm" value="[[!+reg.password_confirm]]" /><br>
	
	<label for="fullname">[[%register.fullname]]<span class="error">[[!+reg.error.fullname]]</span></label> 
	<input id="fullname" type="text" name="fullname" value="[[!+reg.fullname]]" /><br>
	
	<label for="email">[[%register.email]] <span class="error">[[!+reg.error.email]]</span></label> 
	<input id="email" type="text" name="email" value="[[!+reg.email]]" /> <br class="clear" /><br>

	<label for="company">[[%register.company]] <span class="error">[[!+reg.error.company]]</span></label> 
	<input id="company" type="text" name="company" value="[[!+reg.company]]" /> <br>

	
	<div class="form-buttons"><input type="submit" name="registerbtn" value="Register" /></div>

  </form>

</div>

&postHooks=`ExtUserRegisterPosthook

[[!Register? 
&submitVar=`registerbtn` 
&activationResourceId=`16` 
&activationEmailTpl=`tblRegistrationEmail` 
&activationEmailSubject=`Thanks for Registering!` 
&usergroups=`suppliers` 
&validate=`nospam:blank, username:required:minLength=^6^, password:required:minLength=^6^, password_confirm:password_confirm=^password^, fullname:required, email:required:email,company:required:minLength=^3^` 
&placeholderPrefix=`reg.`
&postHooks=`ExtUserRegisterPosthook`]]

<?php
/**
 * Functions as a hook for the Login package which we can use to call Insight.
 */
$insight = $modx->Insight;
if (is_object($insight) && $insight instanceof Insight) {
    $userMail = $hook->getValue('register.email');   
}
/* True must always be returned or account creation via Login will fail */
return true;