Add December Security Release build ID.

Test: make -j49 online-sac-docs
BUG: 32699096
Change-Id: I267203a87535df23401d376159d72c6afe774a9f
diff --git a/src/source/build-numbers.jd b/src/source/build-numbers.jd
index ebbb41f..a921bae 100644
--- a/src/source/build-numbers.jd
+++ b/src/source/build-numbers.jd
@@ -255,6 +255,12 @@
       <td>Pixel XL, Pixel</td>
     </tr>
     <tr>
+      <td>NBD91U</td>
+      <td>android-7.0.0_r24</td>
+      <td>Nougat</td>
+      <td>Nexus 6</td>
+    </tr>
+    <tr>
       <td>N5D91L</td>
       <td>android-7.0.0_r21</td>
       <td>Nougat</td>