Hey everyone!
I created a discord bot to help you create custom coding challenges by combining problem sets from codeforces. The bot takes in the Codeforces handles of the users and the ratings of problems they want to add in the mashup and gives you a set of recent unsolved problems for each rating by the given users. Now, you don't need to manually pick the problems which are unsolved by all the friends/CP peers you're having mashup with!
You can feel free to give any suggestions in the comments section. Here is the github link as well as the discord bot invite link for it. (You can start using the bot by giving a $help command) Hoping that it will be helpful for you all!