re-add babycode guide

app/routes/app.py

@@ -1,4 +1,4 @@
-from flask import Blueprint, redirect, url_for
+from flask import Blueprint, redirect, url_for, render_template
 
 bp = Blueprint("app", __name__, url_prefix = "/")
 
@@ -9,4 +9,4 @@ def index():
 
 @bp.route("/babycode")
 def babycode_guide():
-    return "not yet"
+    return render_template('babycode.html')