Add pre-commit to check app name registered or not

{{cookiecutter.project_slug}}/.pre-commit-config.yaml

@@ -36,3 +36,13 @@ repos:
     hooks:
       - id: detect-secrets
         args: ["--baseline", ".secrets.baseline"]
+
+  - repo: local
+    hooks:
+      - id: check-registered-app
+        name: Check if the app name is registered in fly.io
+        entry: "scripts/check-registered-app-pre-commit.sh"
+        language: python
+        types: [python]
+        require_serial: true
+        verbose: true

{{cookiecutter.project_slug}}/scripts/check-registered-app-pre-commit.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+
+# taken from: https://jaredkhan.com/blog/mypy-pre-commit
+
+# A script for running mypy,
+# with all its dependencies installed.
+
+set -o errexit
+
+# Change directory to the project root directory.
+cd "$(dirname "$0")"/..
+
+./scripts/check-registered-app.sh

{{cookiecutter.project_slug}}/scripts/check-registered-app.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+# Check file registered_app_domain.txt exists. If it does not exists, echo and exit.
+if [ ! -f registered_app_domain.txt ]; then
+  echo -e "\033[0;33mWarning: App name is not registered.\033[0m"
+  echo -e "\033[0;33mGithub Actions may fail if you push without registering.\033[0m"
+  echo -e "\033[0;33mRegister your app name by running the script 'scripts/register_to_fly_io.sh'.\033[0m"
+fi