错误:文件'/composer.phar'不可执行; 请'chmod + x'!

I am deploying my php app on Heroku.

I get this Error :

Writing objects: 100% (784/784), 1.38 MiB | 91.00 KiB/s, done.
Total 784 (delta 137), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> PHP app detected
remote: -----> Bootstrapping...
remote: -----> Installing platform packages...
remote:        NOTICE: No runtime required in composer.json; requirements
remote:        from dependencies in composer.lock will be used for selection
remote:        - php (7.1.0)
remote:        - apache (2.4.20)
remote:        - nginx (1.8.1)
remote: -----> Installing dependencies...
remote:
remote:  !     ERROR: File '/composer.phar' isn't executable; please 'chmod +x'!
remote:
remote:  !     Push rejected, failed to compile PHP app.
remote:
remote:  !     Push failed
remote: Verifying deploy...
remote:
remote: !       Push rejected to secret-mountain-92838.
remote:
To https://git.heroku.com/secret-mountain-92838.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/secret-mountain-92838.git'

When i navigate around every where i get the following answer :

git add . 
git commit -m 'composer.phar removed'
git push heroku master

I have done so, but the error persists. This is my first time to deploy an app on Heroku.

I am using

 - php (7.1.0)
       - apache (2.4.20)
       - nginx (1.8.1)

you need to remove this file of git. Try with

git rm composer.phar

it was my solution

git update-index --chmod=+x composer.phar

(as per comment: ERROR: File '/composer.phar' isn't executable; please 'chmod +x'!)