User logs in

[Remchi]

This feature includes a lot of small tasks:

• [x] react project set up with eslint
• [x] react router and redux setup
• [x] forms and form validation
• [x] several page components: HomePage, SignupPage and DashboardPage
• [x] node js express project setup with babel and eslint
• [x] authentication with JWT
• [x] API for user authentication
• [x] user data, JWT generation
• [x] authorise Routes