Restrict access to unassigned jobs

[ActiveChooN]

My actions before raising this issue

• Read/searched the docs
• Searched past issues

Expected Behaviour

User must not have access to unassigned jobs and see them.

Current Behaviour

Unassigned jobs now is presented in jobs list and users can see them, if they are assigned on some job in the task. But links to unassigned tasks follow to 403 error. It might be a little confusing.

Possible Solution

Filter jobs in a task only with assigned ones.

Steps to Reproduce (for bugs)

1. Create a task as admin with multiple jobs and assign some job to some user.
2. Log in CVAT with that user credentials.
3. Open assigned task
4. Go to any unassigned job

Context

Your Environment

• Git hash commit (git log -1):
• Docker version docker version (e.g. Docker 17.0.05):
• Are you using Docker Swarm or Kubernetes?
• Operating System and version (e.g. Linux, Windows, MacOS):
• Code example or link to GitHub repo or gist to reproduce problem:
• Other diagnostic information / logs:
  Logs from `cvat` container

Next steps

You may join our Gitter channel for community support.

[omersefaozturk]

@azhavoro @ActiveChooN, Is there any improvement or any solution in this matter?