Added index on services.template

This column is queried when creating a new project, without an index
this query would lead to a sequence scan.

db/migrate/20151020145526_add_services_template_index.rb

@@ -0,0 +1,5 @@
+class AddServicesTemplateIndex < ActiveRecord::Migration
+  def change
+    add_index :services, :template
+  end
+end

db/schema.rb

@@ -667,6 +667,7 @@ ActiveRecord::Schema.define(version: 20151026182941) do
 
   add_index "services", ["created_at", "id"], name: "index_services_on_created_at_and_id", using: :btree
   add_index "services", ["project_id"], name: "index_services_on_project_id", using: :btree
+  add_index "services", ["template"], name: "index_services_on_template", using: :btree
 
   create_table "snippets", force: true do |t|
     t.string   "title"