I can't seem to figure out why i get the following error; i've included my controller extension, test class, and VF page.  Can someone help me...it seems like it should be pretty simple? 

Error
System.NullPointerException: Attempt to de-reference a null object. 

Stack Trace:  Class.TrainingAgencyReferralSaveAndThankYou.saveAndThankYou: line 8, column 1
Class.KFGCreateTrainingReferralControllerTest.KFGCreateTrainingReferralControllerTest: line 45, column 1

Controller Extension
public class TrainingAgencyReferralSaveAndThankYou {
Referrals__c referrals;
public TrainingAgencyReferralSaveAndThankYou(ApexPages.StandardController controller){
this.controller = controller;   
}

public PageReference saveAndThankYou() {
Referrals.Online_Referral__c = 'Yes';
controller.save();
PageReference ThankYouPage = Page.TrainingReferralThankYou;
ThankYouPage.setRedirect(true);
return ThankYouPage;
}
private final ApexPages.StandardController controller;
}

Test Class
@isTest
public with sharing class KFGCreateTrainingReferralControllerTest {
    //==================== TEST METHOD(s) ======================================
    static testMethod void KFGCreateTrainingReferralControllerTest() {
     
    Referrals__c newReferrals = new Referrals__c();
    
        // Test insert Referrals__c
        newReferrals.Referral_Date__c = Date.Today();
        newReferrals.Referrer_First_Name__c = 'TestFirstName';
        newReferrals.Referrer_Last_Name__c = 'TestLastName';
        newReferrals.Referrer_Title__c = 'TestTitle';
        newReferrals.Agency__c = 'TestAgency';
        newReferrals.Email__c = 'testemail@test.com';
        newReferrals.Work_Phone__c = '619-111-2222';
        newReferrals.Mobile_Phone__c = '858-999-8888';
        newReferrals.Street_Address__c = 'TestAddress';
        newReferrals.City__c = 'San Diego';
        newReferrals.State__c = 'CA';
        newReferrals.Zip_Code__c = 92111;
        newReferrals.Referral_for_Class_Number__c = 8;
        newReferrals.Client_First_Name__c = 'ClientFirst';
        newReferrals.Client_Last_Name__c = 'ClientLast';
        newReferrals.Client_Phone__c = '800-555-7777';
        newReferrals.Client_Email__c = 'clientemail@test.com';
        newReferrals.Reason_for_Referral__c = 'TestReasonforReferral';
        newReferrals.Why_is_the_Client_Under_Your_Care__c = 'TestWhyUnderCare';
        newReferrals.How_Long_Have_You_Been_Working_Together__c = 'TestHowLongWorkingTogether';
        newReferrals.How_Often_Do_You_Communicate__c = 'TestHowOftenCommunicate';
        newReferrals.How_Often_Do_You_Meet__c = 'TestHowOftenMeet';
        newReferrals.What_Agencies_Do_You_Collaborate_With__c = 'TestAgencyCollaboration';
        newReferrals.What_Are_the_Clients_Goals__c = 'TestClient Goals';
        newReferrals.What_Are_The_Clients_Current_Challenges__c = 'TestClientChallenges';
        newReferrals.Challenges_You_Have_With_the_Client__c = 'TestChallengesWithClient';
        newReferrals.Will_You_Maintain_Collaborative_Support__c = 'Yes';
        newReferrals.Applicant_8_30am_4_30pm_Attendace_Issues__c = 'No';
        newReferrals.Specify_Time_Restrictions_Day_and_Time__c = 'TestTimeDayRestrictions';
        newReferrals.Signature__c = 'TestSignature';
        newReferrals.Date__c = Date.Today();
 insert newReferrals;
 ApexPages.StandardController controller = new ApexPages.StandardController(newReferrals);
    TrainingAgencyReferralSaveAndThankYou testnewReferral = new TrainingAgencyReferralSaveAndThankYou(controller);
    system.assertEquals(Page.TrainingReferralThankYou.getURL(), testnewReferral.saveAndThankYou().getURL());
 System.Assert(newReferrals.Id != null, 'The Referral did not insert properly, please check validation, workflows, etc.');
    System.AssertEquals(newReferrals.Online_Referral__c = 'Yes','The Online Referral field was not able to update.');
    }   
}

VF Page
<apex:page sidebar="false" showHeader="false" standardController="Referrals__c" extensions="TrainingAgencyReferralSaveAndThankYou">  
   <apex:insert name="KFGheader" >
    <c:KFGSiteHeader_Training />
    </apex:insert>
   
            <table class="Header">
            <tr>
            <td class="HeaderTD" style="text-indent: 22px"><b>PROJECT LAUNCH CULINARY JOB TRAINING AGENCY REFERAL FORM</b></td>
            </tr>
            </table>
    <div id="intro">
<!--must update the link to the hard copy attachemnt when done-->
    Please complete all fields before submitting the Agency Referral Form.  Also, if you have not done so already, please have your client complete the Project Launch Culinary Job Training Application.  Applicants can view program requirements and complete their online application at <a href="http://kitchensforgood.org/culinary-job-training/" style="color:blue">http://kitchensforgood.org/culinary-job-training/</a>.  Applicants can also submit a <a href="KFGTrainingApplication" style="color:blue">hard copy application</a> to <a href="training@kitchensforgood.org" style="color:blue">training@kitchensforgood.org</a> or at 404 Euclid Avenue, San Diego, CA 92114.
    </div>
    <apex:form >
    <div id="onlineform">
        <apex:inputHidden value="{!Referrals__c.Online_Referral__c}"/>
    </div>
    <div id="referreragencyinformation">
        First Name<apex:inputfield value="{!Referrals__c.Referrer_First_Name__c}"/>
        Last Name<apex:inputfield value="{!Referrals__c.Referrer_Last_Name__c}"/>
        Title<apex:inputfield value="{!Referrals__c.Referrer_Title__c}"/>
        Agency<apex:inputfield value="{!Referrals__c.Agency__c}"/>
        Email<apex:inputfield value="{!Referrals__c.Email__c}"/>
        Work Phone<apex:inputfield value="{!Referrals__c.Work_Phone__c}"/>
        Mobile Phone<apex:inputfield value="{!Referrals__c.Mobile_Phone__c}"/>       
        Street Address<apex:inputfield value="{!Referrals__c.Street_Address__c}"/>       
        City<apex:inputfield value="{!Referrals__c.City__c}"/>       
        State<apex:inputfield value="{!Referrals__c.State__c}"/>       
        Zip Code<apex:inputfield value="{!Referrals__c.Zip_Code__c}"/>       
    </div>       
   
    <div id="generalreferralandclientinformation">
        Referral Date<apex:inputfield value="{!Referrals__c.Referral_Date__c}"/>
        Referral For Class Number<apex:inputfield value="{!Referrals__c.Referral_for_Class_Number__c}"/>
        Client First Name<apex:inputfield value="{!Referrals__c.Client_First_Name__c}"/>
        Client Last Name<apex:inputfield value="{!Referrals__c.Client_Last_Name__c}"/>
        Client Phone<apex:inputfield value="{!Referrals__c.Client_Phone__c}"/>
        Client Email<apex:inputfield value="{!Referrals__c.Client_Email__c}"/>
    </div>       
    <div id="referrerandclientrelationshipinformation">
        Reason for Referral<apex:inputfield value="{!Referrals__c.Reason_for_Referral__c}"/>       
        Why is the Client Under Your Care<apex:inputfield value="{!Referrals__c.Why_is_the_Client_Under_Your_Care__c}"/>
        How Long Have You Been Working Together<apex:inputfield value="{!Referrals__c.How_Long_Have_You_Been_Working_Together__c}"/>
        How Often Do You Communicate<apex:inputfield value="{!Referrals__c.How_Often_Do_You_Communicate__c}"/>
        How Often Do You Meet<apex:inputfield value="{!Referrals__c.How_Often_Do_You_Meet__c}"/>
        What Other Agencies Do You and Your Client Collaborate With<apex:inputfield value="{!Referrals__c.What_Agencies_Do_You_Collaborate_With__c}"/>
        What Are the Client's Short and Long Term Goals<apex:inputfield value="{!Referrals__c.What_Are_the_Clients_Goals__c}"/>
        What Are the Client's Current Challenges<apex:inputfield value="{!Referrals__c.What_Are_The_Clients_Current_Challenges__c}"/>       
        What Challenges Do You Have With the Client<apex:inputfield value="{!Referrals__c.Challenges_You_Have_With_the_Client__c}"/>       
        Anything Else We Should Know<apex:inputfield value="{!Referrals__c.Anything_Else_We_Should_Know__c}"/>       
    </div>       
    <div id="continuedcollaborationclientattendancesignature">
        Kitchens for Good is a training program, and will not take the place of any social service agency the client is/will be utilizing. Are you willing to maintain collaborative support (maintain an open line of communication, attend meetings, etc.) with Kitchens for Good to promote the overall well-being of the client?<apex:inputfield value="{!Referrals__c.Will_You_Maintain_Collaborative_Support__c}"/>
        Are there any restrictions that would prohibit/interfere with the client’s ability to participate Monday through Friday from 8:30am-4:30pm?<apex:inputfield value="{!Referrals__c.Applicant_8_30am_4_30pm_Attendace_Issues__c}"/>
        Specify Attendance Time Restrictions (Day and Time)<apex:inputfield value="{!Referrals__c.Specify_Time_Restrictions_Day_and_Time__c}"/>
        Signature<apex:inputfield value="{!Referrals__c.Signature__c}"/>
        Date<apex:inputfield value="{!Referrals__c.Date__c}"/>
    </div>       
       
    <apex:commandButton value="Save" action="{!saveAndThankYou}"/>
    </apex:form>   
</apex:page>