Implement the range withen which all the birthdays will be shown off

[UraFIZ]

issue #6

The exapted creatures:

• if we don't provide any diapasone for the bithdays command we will see the 7 days upcoming birthday list
• if we provide, we will see withen this diapasone
• if we run the next command "birthdays fff" we will get the next message: "[ERROR] Invalid command. Use 'help' for more information"
• if we run the "birthdays 11 23 34", the first number will be handled

The space for inhansment:

• we can create more descriptive, meaningful error messages

If we compare this task with what we had in our Python caurse we will see that there is no requriment for checking if the bithday happens within weekend so I did not pay attantion to this point.

[nrkshaman]

Correct : "diapasone" to "range" Not required but possible improvement: add optional argument(flag) to handle weekends

[UraFIZ]

You are right. It's better to use “range” in a tech point of view. Done.