Adding information about PHP errors

.htaccess

@@ -1,3 +1,5 @@
 AuthType NetBadge
 require valid-user
-PubcookieAppId Remediation
+PubcookieAppId Remediation
+#php_flag display_errors on
+#php_value error_reporting 6143

README.textile

@@ -92,12 +92,21 @@ You should now be able to access your application via a web browser.  You'll nee
 
 https://YOUR_WEB_SERVER/YOUR_SUBDIRECTORY/remediate
 
-For example
+For example:
 
 https://www.virginia.edu/mydepartment/remediate
 
 Note the "s" on https!  If NetBadge is correctly enabled, you should see NetBadge authorization occur.  If you get a message that says "We couldn't find your user record.", that means you forgot to put your own computing id into the database (doh!)
 
+If you get a blank screen, it's possible that you have a PHP error occurring, and your server is configured not to display PHP errors (this is a good thing in production, but it makes troubleshooting difficult).  To change this setting, edit the file called ".htaccess" (note that the file begins with a dot), and take out the comment symbols (#) at the beginning of the last two lines:
+
+<pre>
+	php_flag display_errors on
+	php_value error_reporting 6143
+</pre>
+
+Save, and then try reloading your page to see error messages.
+
 h3. Tweaking the verbiage or style
 
 Now that your application is up and running, you will almost certainly want to update the default verbiage.  The relevant files are in the "partials" directory of your application.  In there you will find: