diff --git a/domain-model.md b/domain-model.md
new file mode 100644
index 00000000..047c7981
--- /dev/null
+++ b/domain-model.md
@@ -0,0 +1,18 @@
+# Domain model
+
+Assuming that:
+
+- A userType of 0 is a Bob Bagel's manager
+  - A userType of 1 is the public
+- Bagels are unique; there cannot be two or more of the same bagels in the same basket
+
+| Classes  | Methods                                         | Scenario                                       | Outputs |
+|----------|-------------------------------------------------|------------------------------------------------|---------|
+| `Basket` | `add(String bagel)`                             | Successfully added to basket                   | true    |
+|          |                                                 | Failed to add to basket (e.g., already exists) | false   |
+|          | `remove(String bagel)`                          | Successfully removed from basket               | true    |
+|          |                                                 | Failed to remove from basket                   | false   |
+|          | `isFull()`                                      | Basket is full                                 | true    |
+|          |                                                 | Basket is not full                             | false   |
+|          | `changeCapacity(int newCapacity, int userType)` | Successfully changed capacity of baskets       | true    |
+|          |                                                 | Failed to change capacity of baskets           | false   |
diff --git a/src/main/java/com/booleanuk/core/Basket.java b/src/main/java/com/booleanuk/core/Basket.java
index df7a20aa..c23d503b 100644
--- a/src/main/java/com/booleanuk/core/Basket.java
+++ b/src/main/java/com/booleanuk/core/Basket.java
@@ -1,5 +1,40 @@
 package com.booleanuk.core;
 
+import java.util.ArrayList;
+
 public class Basket {
 
+    private final int DEFAULT_CAPACITY = 10; // Assuming basket has capacity of 10 from beginning
+
+    ArrayList<String> bagels;
+    private int capacity;
+
+    public Basket() {
+        this.bagels = new ArrayList<>();
+        this.capacity = this.DEFAULT_CAPACITY;
+    }
+
+    public boolean add(String bagel) {
+        if (this.bagels.contains(bagel) || this.bagels.size() == this.capacity) {
+            return false;
+        }
+        this.bagels.add(bagel);
+        return true;
+    }
+
+    public boolean remove(String bagel) {
+        return this.bagels.remove(bagel);
+    }
+
+    public boolean isFull() {
+        return this.bagels.size() == this.capacity;
+    }
+
+    public boolean changeCapacity(int newCapcity, int userType) {
+        if (newCapcity < 0 || newCapcity < this.bagels.size() || userType != 0) return false;
+
+        this.capacity = newCapcity;
+        return true;
+    }
+
 }
diff --git a/src/test/java/com/booleanuk/core/BasketTest.java b/src/test/java/com/booleanuk/core/BasketTest.java
index e35771b3..753c1b52 100644
--- a/src/test/java/com/booleanuk/core/BasketTest.java
+++ b/src/test/java/com/booleanuk/core/BasketTest.java
@@ -5,4 +5,89 @@
 
 class BasketTest {
 
+    public BasketTest() {
+
+    }
+
+    @Test
+    public void testAddBagel() {
+        Basket b = new Basket();
+        Assertions.assertTrue(b.add("testBagel"));
+    }
+
+    @Test
+    public void testRemoveBagel() {
+        Basket b = new Basket();
+        b.add("test");
+        Assertions.assertTrue(b.remove("test"));
+    }
+
+    @Test
+    public void testRemoveBagelNotExisting() {
+        Basket b = new Basket();
+
+        Assertions.assertFalse(b.remove("test"));
+    }
+
+    @Test
+    public void testIsBasketFull() {
+        Basket b = new Basket();
+        b.add("test");
+        b.add("test2");
+        b.add("test3");
+        b.add("test4");
+        b.add("test5");
+        b.add("test6");
+        b.add("test7");
+        b.add("test8");
+        b.add("test9");
+        b.add("test10");
+        Assertions.assertTrue(b.isFull());
+    }
+
+    @Test
+    public void testChangeCapacity() {
+        Basket b = new Basket();
+        b.add("test");
+        b.add("test2");
+        b.add("test3");
+        b.add("test4");
+        b.add("test5");
+        b.add("test6");
+        b.add("test7");
+        b.add("test8");
+        b.add("test9");
+        b.add("test10");
+
+        Assertions.assertTrue(b.isFull());
+
+        b.changeCapacity(11, 0);
+
+        Assertions.assertFalse(b.isFull());
+    }
+
+    @Test
+    public void testChangeCapacityInputNotNegative() {
+        Basket b = new Basket();
+
+        Assertions.assertFalse(b.changeCapacity(-1, 0));
+    }
+
+    @Test
+    public void testChangeCapacityNotLessThanBagelsInBasket() {
+        Basket b = new Basket();
+
+        b.add("test");
+        b.add("test2");
+
+        Assertions.assertFalse(b.changeCapacity(1, 1));
+    }
+
+    @Test
+    public void testPublicCannotChangeBasketCapacity() {
+        Basket b = new Basket();
+
+        Assertions.assertFalse(b.changeCapacity(20, 1));
+    }
+
 }