Calendar view

[annagabain]

User Story:

As a user I can view my tasks inside a calendar so that I can remember the dates

Acceptance Criteria:

• [x] The user can see their task headings in the corresponding cell (date) of the month's view
• [x] The user can navigate to the previous and next months
• [x] The user can click tasks
• [x] The clicked link leads to the edit_task/task_id page