Create REST API v1

[pawelgrimm]

Acceptance criteria:

• API v1 spec is implemented

Checklist:

• /users
  • GET /
  • GET /sync
• /sessions
  • GET /
  • GET /:id
  • POST /
  • PATCH /
• /projects
  • GET /
  • GET /:id
  • PATCH /:id
• /tasks
  • GET /
  • GET /:id
  • PATCH /:id