move newrelic + deploytags gem to production env, rename cap tasks to .rake

lib/capistrano/tasks/unicorn.rake

@@ -0,0 +1,20 @@
+namespace :unicorn do
+  desc "Terminate unicorn processes (blocks until complete)"
+  task :terminate do
+    on roles(:app) do
+      execute "[[ -n $(pgrep -f unicorn) ]] && pgrep -f unicorn | xargs kill -SIGTERM"
+      sleep(5)
+    end
+  end
+
+  desc "Kills unicorn processes (blocks until complete)"
+  task :kill do
+    on roles(:app) do
+      execute "[[ -n $(pgrep -f unicorn) ]] && pgrep -f unicorn | xargs kill -SIGKILL"
+    end
+  end
+end
+
+after "deploy:published", "unicorn:terminate"
+after "deploy:published", "unicorn:kill"
+after "deploy:published", "unicorn:start"