Add "boards" context processor

This adds the "boards" context data to all pages, so they can render the
boards nav page.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

threadchat/settings.py

@@ -73,6 +73,7 @@ TEMPLATES = [
                 "django.contrib.auth.context_processors.auth",
                 "django.contrib.messages.context_processors.messages",
                 "board.context_processors.settings",
+                "board.context_processors.boards",
             ],
         },
     },