Update milestone

Author: shunjikonishi

data/milestones.json

@@ -1,22 +1,47 @@
 [
   {
-    "title": "Sprint1",
-    "description": "From 2015/04/13 to 2015/04/26",
-    "due_on": "2015-04-26"
+    "title": "Sprint4",
+    "description": "2015/05/25 to 2015/06/07",
+    "due_on": "2015-06-07"
   },
   {
-    "title": "Sprint2",
-    "description": "2015/04/27 to 2015/05/10",
-    "due_on": "2015-05-10"
+    "title": "Sprint5",
+    "description": "2015/06/08 to 2015/06/21",
+    "due_on": "2015-06-21"
   },
   {
-    "title": "Sprint3",
-    "description": "From 2015/05/11 to 2015/05/24",
-    "due_on": "2015-05-24"
+    "title": "Sprint6",
+    "description": "2015/06/22 to 2015/07/05",
+    "due_on": "2015-07-05"
   },
   {
-    "title": "Sprint4",
-    "description": "2015/05/25 to 2015/06/07",
-    "due_on": "2015-06-07"
+    "title": "Sprint7",
+    "description": "2015/07/06 to 2015/07/19",
+    "due_on": "2015-07-19"
+  },
+  {
+    "title": "Sprint8",
+    "description": "2015/07/20 to 2015/08/02",
+    "due_on": "2015-08-02"
+  },
+  {
+    "title": "Sprint9",
+    "description": "2015/08/03 to 2015/08/16",
+    "due_on": "2015-08-16"
+  },
+  {
+    "title": "Sprint10",
+    "description": "2015/08/17 to 2015/08/30",
+    "due_on": "2015-08-30"
+  },
+  {
+    "title": "Sprint11",
+    "description": "2015/08/31 to 2015/09/13",
+    "due_on": "2015-09-13"
+  },
+  {
+    "title": "Sprint12",
+    "description": "2015/09/14 to 2015/09/27",
+    "due_on": "2015-09-27"
   }
 ]