chore: Migrate authentication to new tables (#1929)

This work provides a foundation for a more pluggable authentication system such as the one outlined in #1317.

closes #1317

server/utils/avatars.js

@@ -0,0 +1,32 @@
+// @flow
+import crypto from "crypto";
+import fetch from "isomorphic-fetch";
+
+export async function generateAvatarUrl({
+  id,
+  domain,
+  name = "Unknown",
+}: {
+  id: string,
+  domain?: string,
+  name?: string,
+}) {
+  // attempt to get logo from Clearbit API. If one doesn't exist then
+  // fall back to using tiley to generate a placeholder logo
+  const hash = crypto.createHash("sha256");
+  hash.update(id);
+  const hashedId = hash.digest("hex");
+
+  let cbResponse, cbUrl;
+  if (domain) {
+    cbUrl = `https://logo.clearbit.com/${domain}`;
+    try {
+      cbResponse = await fetch(cbUrl);
+    } catch (err) {
+      // okay
+    }
+  }
+
+  const tileyUrl = `https://tiley.herokuapp.com/avatar/${hashedId}/${name[0]}.png`;
+  return cbUrl && cbResponse && cbResponse.status === 200 ? cbUrl : tileyUrl;
+}