Include hours and minutes in the expiresAt field

Change-Id: I41799449e720f123bcf6d7c750291ae378c0bd31
diff --git a/src/main/java/com/googlesource/gerrit/plugins/messageoftheday/MessageOfTheDayImpl.java b/src/main/java/com/googlesource/gerrit/plugins/messageoftheday/MessageOfTheDayImpl.java
index a3df2cd..14a8c01 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/messageoftheday/MessageOfTheDayImpl.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/messageoftheday/MessageOfTheDayImpl.java
@@ -67,7 +67,7 @@
       return null;
     }
 
-    if (today().compareTo(expiresAt) > 0) {
+    if (now().compareTo(expiresAt) > 0) {
       return null;
     }
 
@@ -93,7 +93,7 @@
     }
   }
 
-  private static String today() {
-    return new SimpleDateFormat("YYYYMMdd").format(new Date());
+  private static String now() {
+    return new SimpleDateFormat("YYYYMMdd:HHmm").format(new Date());
   }
 }
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index 73b74ab..ea23057 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -11,18 +11,18 @@
 ```
   [message]
     id = hello
-    expiresAt = 20161209
+    expiresAt = 20161209:1730
 ```
 
 message.id
 :	The ID of the current message of the day.
 
 message.expiresAt
-:	Expiration date for the current message of the day. The message will be
-	displayed up to and including that date. The message will not be displayed
-	any more after that date. This field is required. If not set, the message
+:	Expiration date:time for the current message of the day. The message will be
+	displayed up to and including that date:time. The message will not be displayed
+	any more after that date:time. This field is required. If not set, the message
 	will not be displayed.
-	The format of this field is `YYYYMMdd`.
+	The format of this field is `YYYYMMdd:HHmm`.
 
 ## Message content and location