user can enable the ignore_loop_email

app/dashboard/templates/dashboard/setting.html

@@ -382,6 +382,29 @@
     </div>
     <!-- END Always expand alias info -->
 
+    <!-- Ignore Loop Email -->
+    <div class="card" id="ignore-loop-email-section">
+      <div class="card-body">
+        <div class="card-title">Ignore Loop Emails</div>
+        <div class="mb-3">
+          On some email clients, "Reply All" automatically includes your alias that
+          would send the same email to your mailbox.
+          <br>
+          You can disable these "loop" emails by enabling this option.
+        </div>
+        <form method="post" action="#ignore-loop-email-section">
+          <input type="hidden" name="form-name" value="ignore-loop-email">
+          <div class="form-check">
+            <input type="checkbox" id="ignore-loop-email" name="enable"
+                {% if current_user.ignore_loop_email %} checked {% endif %} class="form-check-input">
+            <label for="ignore-loop-email">Ignore Loop Emails</label>
+          </div>
+          <button type="submit" class="btn btn-outline-primary">Update</button>
+        </form>
+      </div>
+    </div>
+    <!-- END Ignore Loop Email -->
+
     <div class="card">
       <div class="card-body">
         <div class="card-title">Quarantine</div>

app/dashboard/views/setting.py

@@ -300,6 +300,15 @@ def setting():
             db.session.commit()
             flash("Your preference has been updated", "success")
             return redirect(url_for("dashboard.setting"))
+        elif request.form.get("form-name") == "ignore-loop-email":
+            choose = request.form.get("enable")
+            if choose == "on":
+                current_user.ignore_loop_email = True
+            else:
+                current_user.ignore_loop_email = False
+            db.session.commit()
+            flash("Your preference has been updated", "success")
+            return redirect(url_for("dashboard.setting"))
 
         elif request.form.get("form-name") == "export-data":
             return redirect(url_for("api.export_data"))