- The user logs in to the app, only by typing the email
    . Additional feature implemented: password is an additional feature (demo password: password)
    
3. The logged-in user is presented with a profile page that includes:
    a. Bookings ("all my transactions")
        - Inside bookings two taps hell to show  
    b. All Courses 
    d. Additional feature: All students '''not available in demo'''

4. When a logged-in user opens "My billable bookings" page:
    a. The total amount of booked minutes is displayed on top.
        i. Additional feature: All equivalent revenue also displayed.
    b. A list of all transactions created by a logged-in user is displayed (sorted by most recent)
    c. Each transaction displays:
        i.  Student name (name), 
        ii. minutes-amount and date, 
        iii. equivalent price per session. 
        iv.  Course's grouping icon (group).
    d. An action button "Add new booking" is displayed

5. When the logged-in user opens "My non-billable booking" page:
    a. A list of all created transactions  by an authenticated  teacher but not assigned to any course (group), or student (user). 
    b. The design of the page is similar to the "My billable bookings."

6. When a logged-in user opens the "All Courses " page:
    a. A list of all courses is displayed in alphabetical order.
        
    b. Each Course displays its icon, name, and record creation date.


7. When a logged-in user opens the "Course transactions" page:
    a. A list of all transactions that belong to that Course is displayed.
    b. The design of the page is similar to the "All my bookings."  Each booking displays the name of the author of the transaction.

8. When a logged-in user opens, "create a new course" or "Add new transaction" page:
    a. A form with all necessary fields is displayed.

9. Additional feature: For create a new course, the following vital data should be provided (among others)
        i. Course name.
        ii. Price per session.
        iii. Session length.
        
10. Additional feature: Signing up students to courses:
    a. Only a professor and course author can enroll students in courses.
    b. Enroll student button is available only on the "course index page"
    c. "add a new transaction" shows on the "course transaction page"
        i. A transaction can be created only for students currently enrolled  into the Course.
        
11. Next release features: Signup of students:
    a. Students will be created only by teachers. Fields will include.
        i. Name
        ii. Email
        iii. Role: student
    ```for simplification this feature is not implemented in the demo```

$ ruby -v

ruby 2.6.5p114 (2019-10-01 revision 67812) [x86_64-linux]