01-b: Add index.erb file

* https://trello.com/c/8VOnWdXl
01-b: Create layout page
01-b: Layout yields to content in the body
01-b: Add title to layout.
01-b: Move contents of app/views to views.

* By default, Sinatra requires this file structure to access erb files.
01-b: Move contents of app/views to views.

* By default, Sinatra requires this file structure to add erb files.
01-b: Render index.erb upon get root request.
01-b: Include gem 'shotgun' under development group.

* Shotgun allows dynamic reloading as pages are developed.
01-b: Add 'choose file' button to index.erb.

* This is probably just a placeholder, but it will be replaced with a functioning button when upload capability is added.