feat: add random generation instances of class Student

app/src/main/java/ru/project/datasource/RandomDataSource.java

@@ -1,11 +1,36 @@
 package ru.project.datasource;
 
 import ru.project.student.Student;
+import ru.project.student.StudentBuilder;
 import ru.project.collection.MyList;
+import java.util.Random;
 
 public class RandomDataSource implements  DataSource{
+    private final String CHARS = "АБВГДЕЖХИКЛМНОПРСТУФХЦЧЩЭЮЯ";
+
+    private String getRandomGroupNumber(Random random){
+        StringBuilder buildRes = new StringBuilder(CHARS.charAt(random.nextInt(CHARS.length())));
+        buildRes.append('-');
+        buildRes.append(String.format("%03d", random.nextInt(999)));
+        return buildRes.toString();
+    }
+    private String getRandomRecordBookNumber(Random random){
+        StringBuilder buildRes = new StringBuilder(CHARS.charAt(random.nextInt(CHARS.length())));
+        buildRes.append(String.format("%08d", random.nextInt(99999999)));
+        return buildRes.toString();
+    }
+
     @Override
     public MyList<Student> fill(int size) {
+        Random random = new Random();
+        MyList<Student> result = new MyList<>();
+        for (short i = 0; i<size; i++){
+            result.add(new StudentBuilder()
+                    .setGroupNumber(getRandomGroupNumber(random))
+                    .setAverageGrade(Math.random() * 5.0)
+                    .setRecordBookNumber(getRandomRecordBookNumber(random))
+                    .build());
+        }
         return null;
     }
 }