🎉 Launch "flatten threads" feature

Fixed: twpowertools:153
Change-Id: I09eb246a4b6de130d5bed81cefe9109995aaf43b
diff --git a/src/options/optionsPage.json5 b/src/options/optionsPage.json5
index 1b4f4d3..9435ece 100644
--- a/src/options/optionsPage.json5
+++ b/src/options/optionsPage.json5
@@ -11,6 +11,7 @@
         {codename: 'threadall'},
         {codename: 'ccdarktheme'},
         {codename: 'threadlistavatars'},
+        {codename: 'flattenthreads'},
         {codename: 'history'},
         {codename: 'perforumstats'},
         {codename: 'batchlock'},