Adapt welcome-tweet script for this year

.travis.yml

@@ -1,4 +1,4 @@
 language: node_js
 cache: yarn
 
-after_success: ./scripts/print_welcome_tweet.sh
+after_success: node ./scripts/print_welcome_tweet.js

scripts/print_welcome_tweet.js

@@ -0,0 +1,32 @@
+const fs = require("fs");
+const path = require("path");
+const glob = require("glob");
+const DIR = "_data/events_gdcr2019";
+
+const toWelcomeTweetModerators = moderators => {
+  const names = moderators.map(mod => {
+    if (typeof mod === "string") return mod;
+    if (mod.url.includes("twitter.com"))
+      return "@" + mod.url.split("/").slice(-1)[0];
+    return mod.name;
+  });
+  if (names.length === 1) return names[0];
+  return names.slice(0, -1).join(", ") + " & " + names.slice(-1)[0];
+};
+
+const toWelcomeTweet = event => {
+  const moderators = toWelcomeTweetModerators(event.moderators);
+  return `🌐 Welcome ${event.location.city}, ${
+    event.location.country
+  } with ${moderators} to the Global Day Of Coderetreat 2019! #gdcr19 #coderetreat ${
+    event.url
+  }`;
+};
+
+const events = glob
+  .sync(path.resolve(__dirname, "../_data/events_gdcr2019/") + "/*.json")
+  .sort((fa, fb) => fs.statSync(fa).mtimeMs - fs.statSync(fb).mtimeMs)
+  .map(file => JSON.parse(fs.readFileSync(file)))
+  .map(toWelcomeTweet);
+
+console.log(events.join("\n"));