Add rss feed

[curibe]

Add rss feed to monadical's blog

The following changes were made to add the rss feed:

• A new endpoint in flask: /posts/feed.xml, and use the feedgen library to generate the xml.
• In the build file:
  • Run wget to save the feed.xml inside the output posts/ folder.
• Add the feedgen library installation in the file .github/workflows/deploy.yml and requirements.txt

[curibe]

@pirate, the xml generation is encapsulated in an endpoint, and therefore I need to make a request to that endpoint in the build file with the wget command. Another option would be to implement that function in a standard way and not as an endpoint and execute it before the app.run(). This is because the feedgen library can generate the xml as a file. Anyway, both ways can create the xml inside the posts/ folder