Improve user page navigation menu

Add counts to edits, blocks, and traces; don't show blocks if there
are none; and move OAuth to the settings page.

db/migrate/20120808231205_add_counter_caches.rb

@@ -0,0 +1,19 @@
+class AddCounterCaches < ActiveRecord::Migration
+  def self.up
+    add_column :users, :changesets_count, :integer, :null => false, :default => 0
+    add_column :users, :traces_count, :integer, :null => false, :default => 0
+
+    Changeset.group(:user_id).pluck(:user_id).each do |user_id|
+      User.reset_counters(user_id, :changesets)
+    end
+
+    Trace.group(:user_id).pluck(:user_id).each do |user_id|
+      User.reset_counters(user_id, :traces)
+    end
+  end
+
+  def self.down
+    remove_column :users, :changesets_count
+    remove_column :users, :traces_count
+  end
+end