(feat) Add task through UI

[schmidyy]

Be able to add task through the UI. The scope of this is exclusively:

1. when looking at a project you have a button on a section header to add a task within the given section
2. behaviour should mimic asana
3. submit will save the task to the section but you can still edit it by selecting it

[NickLewanowicz]

@hughxie make sure that you are providing a 'position' attribute when creating a task. For now you can make it a the .toString() of the section.length.