Added stub release notes for 1.8.4

docs/releases/1.8.4.txt

@@ -0,0 +1,12 @@
+==========================
+Django 1.8.4 release notes
+==========================
+
+*Under development*
+
+Django 1.8.4 fixes several bugs in 1.8.3.
+
+Bugfixes
+========
+
+* ...

docs/releases/index.txt

@@ -32,6 +32,7 @@ versions of the documentation contain the release notes for any later releases.
 .. toctree::
    :maxdepth: 1
 
+   1.8.4
    1.8.3
    1.8.2
    1.8.1