README: fix links

README.md

@@ -8,54 +8,54 @@ Contents of this repository are based on [Java programming course material](http
 
 ## Contents
 
-- [Basics](src/branch/master/1_basics)
+- [Basics](1_basics)
 
     - Description: fundamental code structuring
 
-- [Conditionals](src/branch/master/2_conditionals)
+- [Conditionals](2_conditionals)
 
     - Description: conditionals in Java
 
-- [Loops](src/branch/master/3_loops)
+- [Loops](3_loops)
 
     - Description: `for` and `while` loops in Java
 
-- [Strings](src/branch/master/4_strings)
+- [Strings](4_strings)
 
     - Description: String operations in Java
 
-- [Lists](src/branch/master/5_lists)
+- [Lists](5_lists)
 
     - Description: List operations in Java
 
-- [Arrays](src/branch/master/6_arrays)
+- [Arrays](6_arrays)
 
     - Description: Array operations in Java
 
-- [Methods](src/branch/master/7_methods)
+- [Methods](7_methods)
 
     - Description: Methods in Java
 
-- [Lottery](src/branch/master/8_lottery_bonus)
+- [Lottery](8_lottery_bonus)
 
     - Description: Two bonus assignments
 
-- [Command line tools](src/branch/master/9_clitools)
+- [Command line tools](9_clitools)
 
     - Description: Basic day checker
 
-- [Classes and objects](src/branch/master/10_classes-and-objects)
+- [Classes and objects](10_classes-and-objects)
 
     - Description: Custom classes and objects in Java
 
-- [Object-oriented programming](src/branch/master/11_object-oriented_programming)
+- [Object-oriented programming](11_object-oriented_programming)
 
     - Description: Multi-class Java programs
 
-- [Exception](src/branch/master/12_exception)
+- [Exception](12_exception)
 
     - Description: Exception handling in Java
 
-- [Files](src/branch/master/13_files)
+- [Files](13_files)
 
     - Description: File reading in Java