[BE] Parse JSON with source links and RegEx for the article links

[KenanBek]

Goal

Load list of the source links from JSON file.

Format of the JSON:

[{
    "website": "http://highscalability.com/",
    "article_regex": "<post regex for highscalability.com>"
}, {
    "website": "https://news.ycombinator.com/",
    "article_regex": "<post regex for news.ycombinator.com>"
}]

Also, the temporary command needs to be added for the initializing parse of JSON with the following article parse step (another issue)

Follow-up

• load list of the source links from the database instead of JSON file