add files

app/controllers/api/v0/tags_controller.rb

+class Api::V0::TagsController < ApplicationController
+  def show
+
+  end
+end

spec/controllers/api/v0/tags_controller_spec.rb

+#   Copyright (c) 2010-2011, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
+
+require 'spec_helper'
+
+describe Api::V0::TagsController do
+  describe '#show' do
+    it 'succeeds' do
+      get :show, :name => 'alice'
+      response.should be_success
+    end
+
+    it "returns the basic tag data" do
+      get :show, :name => 'alice'
+      parsed_json = JSON.parse(response.body)
+      parsed_json.keys.should =~ %w(name person_count followed_count posts)
+    end
+  end
+end