Hello, I'm trying to extend BlogModule, but it doesn't work.
What I've done thus far:

BlogEntryDecorator:

<?php
class BlogEntryDecorator extends SiteTreeDecorator {
function extraStatics() {
   return array(
    'static $db' => array(
      "Source" => "Text",
      "SourceURL" => "Text"
    ),
   
'has_one' => array(
'Photo' => 'Image'      
)
);
}

function updateCMSFields(& $fields){
    $fields->addFieldToTab("Root.Content.Main", new TextField("Source"));
    $fields->addFieldToTab("Root.Content.Main", new TextField("SourceURL));
$fields->addFieldToTab("Root.Content.Image", new SimpleImageField('Photo','An image for this Blog Entry'));
}
}

added DataObject::add_extension('BlogEntry', 'BlogEntryDecorator'); to _config.php

BlogSummary.ss:

<div class="blogSummary">
...
...
   <% if BlogEntryImage %>
      <% control BlogEntryImage %>$CroppedImage(79,89) <% end_control %>
   <% end_if %>
   $Photo
   $ParagraphSummary
   <a href="$SourceURL">$Source</a>
...
...
</div>

When creating new form I get SimpleImageField for entering photo and 2 fields to enter source and sourceurl.
When going to /admin I see the image properly uploaded, but source and sourceurl fields are empty
Nothing shows on site
Please Help!

OK, I have solved all of the problems.
For some reason there was a bug:
The template NewsHolder.ss (NewsHolder.php extends BlogHolder and .ss templates are basically the same) was including the wrong BlogSummary.ss (the one in /blog/templates/includes instead the one in /templates/blackcandy_blog/templates/includes folder; after renaming it to BlogSummary1.ss and including that one it didn't include anything, then I created new file, named it BlogSummary2.ss, copy-pasted all from BlogSummary1.ss to new BlogSummary2.ss and included that one all of it worked - be4 I did it I checked the permissions BlogSummary1.ss had and all seemed fine, I just can't figure it out why it hasn't worked, but it is working now)

Topic can be closed, ty!