Updating README with instructions and showcases

This extension will now be built and released for both Furbooru and
Derpibooru as 2 separate extensions.

README.md

@@ -1,10 +1,47 @@
-# Furbooru Tagging Assistant
+# Philomena Tagging Assistant
+
+This is a browser extension written for the [Furbooru](https://furbooru.org) and [Derpibooru](https://derpibooru.org) 
+image-boards. It gives you the ability to manually go over the list of images and apply tags to them without opening 
+each individual image.
+
+## Installation
+
+This extension is available for both Chromium- and Firefox-based browsers. You can find the links to the extension pages
+below.
+
+### Furbooru Tagging Assistant
 
 [![Get the Add-on on Firefox](.github/assets/firefox.png)](https://addons.mozilla.org/en-US/firefox/addon/furbooru-tagging-assistant/)
 [![Get the extension on Chrome](.github/assets/chrome.png)](https://chromewebstore.google.com/detail/kpgaphaooaaodgodmnkamhmoedjcnfkj)
 
-This is a browser extension written for the [Furbooru](https://furbooru.org) image-board. It gives you the ability to
-tag the images more easily and quickly.
+### Derpibooru Tagging Assistant
+
+I wasn't able to release the extension for Derpibooru yet. Links will be available shortly.
+
+## Features
+
+### Tagging Profiles
+
+Select a set of tags and add/remove them from images without opening them. Just hover over image, click on tags and 
+you're done!
+
+![Tagging Profiles Showcase](.github/assets/profiles-showcase.png)
+
+### Custom Tag Groups
+
+Customize the list of tags with your own custom tag groups. Apply custom colors to different groups or even separate 
+them from each other with group titles.
+
+![Tag Groups Showcase](.github/assets/groups-showcase.png)
+
+### Fullscreen Viewer
+
+Open up the specific image or video in fullscreen mode by clicking 🔍 icon in the bottom left corner of the image. This 
+feature is opt-in and should be enabled in the settings first.
+
+![Fullscreen Viewer Icon](.github/assets/fullscreen-viewer-icon.png)
+
+![Fullscreen Viewer Showcase](.github/assets/fullscreen-viewer-showcase.png)
 
 ## Building
 
@@ -19,11 +56,18 @@ npm install --save-dev
 ```
 
 Second, you need to run the `build` command. It will first build the popup using SvelteKit and then build all the 
-content scripts/stylesheets and copy the manifest afterward. Simply run:
+content scripts/stylesheets and copy the manifest afterward.
+
+Extension can currently be built for 2 different imageboards using one of the following commands:
 
 ```shell
+# To build the extension for Furbooru, use:
 npm run build
+
+# To build the extension for Derpbooru, use:
+npm run build:derpibooru
 ```
 
-When building is complete, resulting files can be found in the `/build` directory. These files can be either used 
-directly in Chrome (via loading the extension as unpacked extension) or manually compressed into `*.zip` file.  
+When build is complete, extension  files can be found in the `/build` directory. These files can be either used 
+directly in Chrome (via loading the extension as unpacked extension) or manually compressed into `*.zip` file and loaded
+into Firefox.