Refactor project to new name

The name of the project is being refactored from Privacy Revolver to
Farside. The reasoning behind this is:
1. A shorter name is easier to remember
2. It can stand for "FOSS alternative redirecting service" (which I know
doesn't encapsulate all letters from "farside", but it's close enough).

This commit also includes improvements to the update script for
determining how far along the script is.

lib/farside/router.ex

@@ -0,0 +1,51 @@
+defmodule Farside.Router do
+  @fallback_str Application.fetch_env!(:farside, :fallback_str)
+
+  use Plug.Router
+
+  plug(:match)
+  plug(:dispatch)
+
+  get "/" do
+    send_resp(conn, 200, "")
+  end
+
+  get "/ping" do
+    # Useful for app healthcheck
+    {:ok, resp} = Redix.command(:redix, ["PING"])
+    send_resp(conn, 200, resp)
+  end
+
+  get "/:service/*glob" do
+    path = Enum.join(glob, "/")
+
+    {:ok, instances} =
+      Redix.command(
+        :redix,
+        ["LRANGE", service, "0", "-1"]
+      )
+
+    # Either pick a random available instance, 
+    # or fall back to the default one
+    instance =
+      if Enum.count(instances) > 0 do
+        Enum.random(instances)
+      else
+        {:ok, result} =
+          Redix.command(
+            :redix,
+            ["GET", "#{service}#{@fallback_str}"]
+          )
+
+        result
+      end
+
+    # Redirect to the available instance
+    conn
+    |> Plug.Conn.resp(:found, "")
+    |> Plug.Conn.put_resp_header(
+      "location",
+      "#{instance}/#{path}"
+    )
+  end
+end