Add a note field to View (#28)

- Labeled as 'Where We Landed' in the UI
Add ability to render text as markdown (#28)

- Implemented with Redcarpet gem
- Render View#note as markdown
Fix some wonky view spacing.
Move #markdown from ApplicationController to ApplicationHelper
Add a test to ensure correct rendering of Markdown

Thanks @efatsi for the suggestion!
Add Interaction CRUD & DRY up duplicated View Resource code

- Interaction CRUD
- Interactions, wireframes, and comps are identical (all View Resources) - DRY'd it up
- Created shared_example model and feature specs for view resources
Styles where we landed field
Fixes display of where we landed textarea
Moved header bar margin to placeholder selector
Create Checklist model

- Also added the foreigner gem for FK support in migrations
Add .DS_Store
Add controller + view-related code for Checklists
Update based on PR#9 feedback

- Change set_project to trigger for all actions in ChecklistsController
- Refactor set_project_and_checklist in ChecklistsController
- Add an attr_reader + helper_method for checklists in ChecklistsController
- Add another check to ensure users can get to an edit page from the Checklist index page
Model-level implementation of StatusCategory and StatusItem

- StatusCategories are polymorphic as categorizable
- Checklists are the first thing to be categorizable
- StatusItems are polymorphic as statusable
- Views are the first thing to be statusable
- The status of a StatusItem can be represented as either boolean or string
- StatusCategories can toggle the status type for all associated StatusItems
Wire up controller and view code for StatusCategories and StatusItems
Break before_action :set_status_item into memoizing reader methods and move view-specific methods to
a helper

Thanks @zporter
Remove `array_of_` from the #create_status_items_for input variable name
Remove unnecessary whitespace
Use memoized helper methods
Remove dependent: :destroy from :status_category association