code: def init_app(app, env=None):
      
      # Make current_auth available to app templates
      app.jinja_env.globals['current_auth'] = current_auth
      # Make the current view available to app templates
      app.jinja_env.globals['current_view'] = current_view
      # Disable Flask-SQLAlchemy events.
      # Apps that want it can turn it back on in their config
      app.config.setdefault('SQLALCHEMY_TRACK_MODIFICATIONS', False)
      # Load config from the app's settings.py
      load_config_from_file(app, 'settings.py')
      # Load additional settings from the app's environment-specific config file
      if not env:
          env = environ.get('FLASK_ENV', 'DEVELOPMENT')  # Uppercase for compatibility with Flask-Environments
      additional = _additional_config.get(env.lower())  # Lowercase because that's how we define it
      if additional:
          load_config_from_file(app, additional)
  
      logger.init_app(app)
docs: Configure an app depending on the environment. Loads settings from a file
      named ``settings.py`` in the instance folder, followed by additional
      settings from one of ``development.py``, ``production.py`` or
      ``testing.py``. Typical usage::
  
          from flask import Flask
          import coaster.app
  
          app = Flask(__name__, instance_relative_config=True)
          coaster.app.init_app(app)  # Guess environment automatically
  
      :func:`init_app` also configures logging by calling
      :func:`coaster.logger.init_app`.
  
      :param app: App to be configured
      :param env: Environment to configure for (``'development'``,
          ``'production'`` or ``'testing'``). If not specified, the ``FLASK_ENV``
          environment variable is consulted. Defaults to ``'development'``.