Added a discussion stylesheet and linked to it in application.scss

sass/_discussion.scss

@@ -0,0 +1,3 @@
+secondaryHeader {
+  @extend .topbar;
+}

sass/application.scss

@@ -13,6 +13,7 @@
 @import "profile";
 @import "wiki-create", "wiki";
 @import "activation";
+@import "discussion";
 
 // left over
 @import "theme";