Remove 404 idea links

Author: woojiahao

ideas.md

@@ -5,7 +5,6 @@
 ## An extended list of project ideas:
 - [20 Exciting Software Development Project Ideas & Topics for Beginners](https://www.upgrad.com/blog/software-development-project-ideas-topics-for-beginners/)
 - [40 Side Project Ideas for Software Engineers](https://www.codementor.io/npostolovski/40-side-project-ideas-for-software-engineers-g8xckyxef)
-- [App Ideas Collection](https://www.ideaswatch.com/startup-ideas/online-ideas)
 - [Make your own...](https://github.com/danistefanovic/build-your-own-x)
 - [Practical Projects](https://github.com/karan/Projects)
 - [1000+ Beginner Programming Projects](https://www.reddit.com/r/learnprogramming/comments/2a9ygh/1000_beginner_programming_projects_xpost/)
@@ -14,4 +13,3 @@
 - [Rosetta Code](http://rosettacode.org/wiki/Category:Programming_Tasks)
 - [Epic List Of Side Project Ideas For Programmers](https://livingliferichly.com/epic-list-of-side-project-ideas-for-programmers)
 - [5 project ideas](https://medium.com/@JohanneA/5-project-ideas-for-programmers-who-dont-know-what-to-work-on-next-51fdb191cbde)
-- [6 project ideas to help you write creative code](https://blog.kadenze.com/creative-technology/6-projects-to-help-you-learn-creative-code/)