Begin working on Habit Screens project

Created a small MVP for digitizing my weekly habits. Much more to come.

Lots of things happening:

- Copied the boilerplate to get started
- Added a brief project-level README
- Outlined my ambitions in design.md

See README and design.md for more context on this project.

scratch/habit-screens/design.md

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+# Habit Screens
+
+## MVP
+
+One Android tablet mounted on my bedroom wall displaying habits for that day. I
+can toggle the done/todo states on each item by tapping it. There is no
+server. All of the habits are defined in the client-side codebase. The
+application is available online at wpcarro.dev.
+
+## Ideal
+
+Three Android tablets: one mounted in my bedroom, another in my bathroom, and a
+third in my kitchen. Each tablet has a view of the current state of the
+application and updates in soft real-time.
+
+I track the rates at which I complete each habit and compile all of the metrics
+into a dashboard. When I move a habit from Saturday to Sunday or from Wednesday
+to Monday, it doesn't break the tracking.
+
+When I complete a habit, it quickly renders some consistency information like
+"completing rate since Monday" and "length of current streak".
+
+I don't consider this application that sensitive, but for security purposes I
+would like this application to be accessible within a private network. This is
+something I don't know too much about setting up, but I don't want anyone to be
+able to visit www.BillAndHisHabits.com and change the states of my habits and
+affect the tracking data. Nor do I want anyone to be able to make HTTP requests
+to my server to alter the state of the application without my permission.
+
+## Client
+
+Language: Elm
+
+### Updates across devices
+
+Instead of setting up sockets on my server and subscribing to them from the
+client, I think each device should poll the server once every second (or fewer)
+to maintain UI consistency.
+
+## Server
+
+Language: Haskell
+Database: SQLite