add timestamp field to solution

service/src/main/java/com/telephoners/krakyournet/ctf/beans/Solution.java

@@ -2,6 +2,7 @@ package com.telephoners.krakyournet.ctf.beans;
 
 import com.telephoners.krakyournet.ctf.beans.tasks.Task;
 import org.bson.types.ObjectId;
+import org.joda.time.Instant;
 import org.mongodb.morphia.annotations.Entity;
 import org.mongodb.morphia.annotations.Id;
 
@@ -15,12 +16,14 @@ public class Solution
     private Task task;
     private Team team;
     private Flag flag;
+    private Instant submitionTime;
 
     public Solution(Team team, Task task, Flag flag)
     {
         this.team = checkNotNull(team);
         this.task = checkNotNull(task);
         this.flag = checkNotNull(flag);
+        this.submitionTime = Instant.now();
     }
 
     public Solution()
@@ -56,4 +59,14 @@ public class Solution
     {
         this.flag = flag;
     }
+
+    public Instant getSubmitionTime()
+    {
+        return submitionTime;
+    }
+
+    public void setSubmitionTime(Instant submitionTime)
+    {
+        this.submitionTime = submitionTime;
+    }
 }