Add mechanism for discovering tools in Canvas account, creating stub LtiTool records (#9)

[roujiawang]

9

To Do

• [x] Pull data from Canvas
• [x] Create instances using QuerySet API
• [x] Create a Django management command that pulls data and creates instances
• [x] Add public or visibility flag, set default to true, set all new instances created by process to false.
  • [x] In models, add public BooleanField field for LTI Tool instances, and set this field to False by default.
  • [x] For admin, display this field, and allow quick actions to change the value of this field for multiple instances.
  • [x] In views, add a filter so that user view only lists tools whose public field is set to true.
  • [x] Initial check on if this would affect any existing tool instance or newly-created tool instance in any negative way.
    • [x] Able to create a new instance with the field set to True or set to False, and the tool will display/hide accordingly in user view
    • [x] Able to change the field of an existing instance by visiting it or by actions, and the tool will display/hide accordingly in user view
    • [x] The tool still needs a valid Canvas id to display; that is, some tool with an invalid Canvas id will not display to users even if this field is set as 'True'
• [ ] Move canvasapi code into CanvasLtiManager or another adapter class
  • [ ] Create a custom class to encapsulate operations.
  • [ ] Adopt this class in the commands method.
• [ ] Find a way to trigger process with a button in admin UI, use admin's Canvas token

[jonespm]

Good start on this feature idea! I'm sure we'll have a few more things to talk about with this and to get through the other ToDo items.