Do you want to use such tool?
It will be some tool with product backlog, sprint backlogs, Scrum/Kanban dashboard... Me and my partners want to develop this.
I'd strongly advice to think it through. There are many Kanban/Scrum tools already - here you can find pretty comprehensive list: limited WIP society tools
Also, when we're discussing Kanban many teams tend to work with physical board and not software as long as that's possible. But of course there are also those which can't and have to fall back to some kind of application.
Anyway, for me this niche looks pretty crowded already and unless you have a good idea for differentiator - something which would make distinguishable from others and would the best of breed at least for some specific group of end-users (teams) - it doesn't sound like the best app you can build.
All credit to Stanislav for asking the question before starting a development that ends up with no customers.
@Stanislav, if you and your partners want to develop it, you must feel that there is a market, so I suggest defining your market and carrying out some more market research before committing any time or effort to starting the work. Make sure you think through how the tool will be used, and not just what it will do (ie what is the use case): that might help to identify the differentiator that you need to justify the work, and it may also help with the subsequent marketing of the product, should you build it.
I wonder why all people discourage you from development such a tool. Definitely there is a market. And yes, it is quite crowded. However, that should be not a show stopper. Maybe you have unique vision with clear focus. Maybe only you can create best app in this category. I would not listen to such advices, but rather think about "do I really want to create such an app?". If answer is yes, you should go ahead.