Show flash after generating static files

assets/scss/style.scss

 $white:       #ffffff;
 $blue:        #496893;
 $red:         #d9534f;
+$green:       #5cb85c;
 $light-gray:  #f5f5f5;
 $medium-gray: #c8c8c8;
 
   margin-bottom: 15px;
 }
 
+/* errors & flashes */
+
+.notice,
 .error {
   align-items: center;
   color: $white;
   background: $red;
 }
 
+.notice {
+  background: $green;
+}
+
+.notice__message,
 .error__message {
   flex: 1;
 }

yird/app.py

-from flask import Flask, redirect, render_template, request, url_for
+from flask import Flask, flash, redirect, render_template, request, url_for
 
 from flask_webpack import Webpack
 
 
 params = {
     'DEBUG': True,
-    'WEBPACK_MANIFEST_PATH': '../manifest.json'
+    'WEBPACK_MANIFEST_PATH': '../manifest.json',
+    'SECRET_KEY': b'flasndfjlasfnlajsnfs'
 }
 app.config.update(params)
 
 @app.route('/admin/generate')
 def generate():
     PostsService.generate_posts()
+    flash('Generated static files successfully')
+    return redirect(url_for('index'))
 
 
 @app.route('/admin/repo', methods=["GET"])

yird/templates/layout.html.j2

           </form>
         </p>
       {% endif %}
+      {% with messages = get_flashed_messages() %}
+        {% if messages %}
+          {% for message in messages %}
+            <div class="notice">
+              <p class="notice__message">{{ message }}</p>
+            </div>
+          {% endfor %}
+        {% endif %}
+      {% endwith %}
     </header>
     <main class="main">
       {% block content %}{% endblock %}