Fix brew server and document.

Library/Contributions/examples/brew-server

@@ -144,7 +144,7 @@ get '/formula/:name' do
     end
   end
 
-  used_by = Formula.get_used_by()[klass.name]
+  used_by = Formula.all.select{|ff| ff.deps.include?(klass.name)}.map{|f| f.name}.flatten.uniq.sort
   unless used_by == nil
     s << <<-HTML
             <dt>Used by</td>

Library/Contributions/manpages/brew.1.md

@@ -175,6 +175,10 @@ Some external commands are shipped with Homebrew, and enabled by default.
   * `missing`:
     Checks all installed formuale for missing dependencies.
 
+  * `server`:
+    Starts a local webserver with an app that lets you browse available
+    formulae, similar to `gem server`.
+
   * `test` <formula>:
     A few formulae provide a test method. `brew test <formula>` runs this
     test method. There is no standard output or return code, but it should

share/man/man1/brew.1

@@ -186,6 +186,10 @@ Downloads the tarball or checks out from VCS for the given \fIformula\fR\. For t
 Checks all installed formuale for missing dependencies\.
 .
 .TP
+\fBserver\fR
+Starts a local webserver with an app that lets you browse available formulae, similar to \fBgem server\fR\.
+.
+.TP
 \fBtest\fR \fIformula\fR
 A few formulae provide a test method\. \fBbrew test <formula>\fR runs this test method\. There is no standard output or return code, but it should generally indicate to the user if something is wrong with the installed formula\.
 .