[Feature request] Estimated and spent hours

Hello,

I have started to use quire.io and I'm very happy because of the simple ui and great ux!

I'm a freelancer developer and every time my clients ask me: "How much time do you need to complete these tasks?"

So I have to give them

• an estimation at the begining of the project
• a list about the completed tasks with the spent hours at the end of the project.

Tags can be good enough to mark originally estimated and not-estimated tasks at the end of the project.

I believe that this feature would be greatful for the users and marketability:

• optionally fill estimated and spent hours of the tasks. Summarized hours should be shown in parent/grandparent/etc tasks.