Implement project Professional_L1.1 (Collections)
Add and implement classes Month.cs and Year.cs
Update gitignor
Improve project Professional_L1.1 (Collections)
Delete class Year.cs
Implement static class CollectionGenericMonthExtensions.cs
Improve project by using LINQ
Merge pull request #55 from anna-kulyk/LP1.1

Implement project Professional_L1.1 (Collections)