add discord_handler

lib/zoeyscomputer_web/plugs/discord_handler.ex

@@ -0,0 +1,24 @@
+defmodule ZoeyscomputerWeb.DiscordHandler do
+  import Plug.Conn
+
+  def init(opts), do: opts
+
+  def call(%{path_info: ["images", _id]} = conn, _opts) do
+    case get_req_header(conn, "user-agent") do
+      ["Mozilla/5.0 (compatible; Discordbot/" <> _rest] -> handle_discord(conn)
+      _ -> conn
+    end
+  end
+
+  def call(conn, _opts), do: conn
+
+  defp handle_discord(%{path_info: ["images", id]} = conn) do
+    url = "https://s3.zoeys.computer/imgs/uploads/#{id}.png"
+
+    conn
+    |> put_resp_header("location", url)
+    |> put_resp_content_type("text/plain")
+    |> send_resp(302, "Redirecting to image")
+    |> halt()
+  end
+end