Add Domain Core Classes And Common Domain Module.

common/common-domain/src/main/java/com/food/order/domain/exception/DomainException.java

@@ -0,0 +1,12 @@
+package com.food.order.domain.exception;
+
+public class DomainException extends RuntimeException {
+
+    public DomainException(String message) {
+        super(message);
+    }
+
+    public DomainException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

common/common-domain/src/main/java/com/food/order/domain/valueobject/Money.java

@@ -8,6 +8,8 @@ public class Money {
 
     private final BigDecimal amount;
 
+    public static final Money ZERO = new Money(BigDecimal.ZERO);
+
     public Money(BigDecimal amount) {
         this.amount = amount;
     }