herokuにphpのデプロイをするとForbidden You don't have permission to access this resource.と出る

###herokuに作成したphpをデプロイしたい

PHPのシステムを作成して，herokuにデプロイして仮動作をさせようとしたのですが
herokuにデプロイしheroku openで開くとエラーが出てしまった．

発生している問題・エラーメッセージ

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pushした際に出た警告

remote:  !     WARNING: Composer vendor dir found in project!
remote:  !
remote:  !     Your Git repository contains Composer's 'vendor' directory.
remote:  !
remote:  !     This directory should not be under version control; only your
remote:  !     'composer.json' and 'composer.lock' files need to be added, as
remote:  !     Composer will handle installation of dependencies on deploy.
remote:  !
remote:  !     To suppress this notice, first remove the folder from the index
remote:  !     by running 'git rm -r --cached vendor/'.
remote:  !     Next, edit your project's '.gitignore' file and add the folder
remote:  !     '/vendor/' to the list, then commit the changes.
remote:  !
remote:  !     For more info, refer to the Composer FAQ: http://bit.ly/1rlCSZU
remote:
remote:        Loading composer repositories with package information
remote:        Installing dependencies from lock file
remote:        Nothing to install or update
remote:        Generating optimized autoload files
remote: -----> Preparing runtime environment...
remote:        NOTICE: No Procfile, using 'web: heroku-php-apache2'.
remote: -----> Checking for additional extensions to install...
remote: -----> Discovering process types
remote:        Procfile declares types -> web