Handle feed URL redirects

Closes #1

lib/frenzy/update_feeds.ex

@@ -74,6 +74,17 @@ defmodule Frenzy.UpdateFeeds do
       {:ok, %HTTPoison.Response{status_code: 404}} ->
         Logger.warn("RSS feed #{feed.feed_url} not found")
 
+      {:ok, %HTTPoison.Response{status_code: status_code}} when status_code in [301, 302] ->
+        {"Location", new_url} =
+          Enum.find(headers, fn {name, _value} ->
+            name == "Location"
+          end)
+
+        Logger.debug("Got 301 redirect from #{url} to #{new_url}, updating feed URL")
+        changeset = Feed.changeset(feed, %{feed_url: new_url})
+        {:ok, feed} = Repo.insert(changeset)
+        update_feed(feed)
+
       {:error, %HTTPoison.Error{reason: reason}} ->
         Logger.error("Couldn't load RSS feed: #{reason}")
     end
@@ -200,7 +211,7 @@ defmodule Frenzy.UpdateFeeds do
         {:err, "404 not found"}
 
       {:ok, %HTTPoison.Response{status_code: status_code, headers: headers}}
-      when status_code == 301 or status_code == 302 ->
+      when status_code in [301, 302] ->
         {"Location", new_url} =
           Enum.find(headers, fn {name, _value} ->
             name == "Location"