Tell people about update bug in README/issue template.

.github/ISSUE_TEMPLATE.md

@@ -1,3 +1,5 @@
+If Homebrew was updated on Aug 10-11th 2016 and `brew update` always says `Already up-to-date.` you need to run: `cd $(brew --repo); git fetch; git reset --hard origin/master; brew update`.
+
 # Please follow the general troubleshooting steps first:
 
 - [ ] Ran `brew update` and retried your prior step?

README.md

@@ -1,6 +1,12 @@
 # Homebrew Core
 Core formulae for the Homebrew package manager.
 
+## Update Bug
+If Homebrew was updated on Aug 10-11th 2016 and `brew update` always says `Already up-to-date.` you need to run:
+```bash
+cd $(brew --repo); git fetch; git reset --hard origin/master; brew update
+```
+
 ## How do I install these formulae?
 Just `brew install <formula>`. This is the default tap for Homebrew and is installed by default.