I have the following .gitlab-ci.yml file:

stages:
  - pull
  - optimize

variables:
  GIT_SSL_NO_VERIFY: "1"

before_script:
  - git config --global http.sslVerify false
  - git config --global credential.helper store
  - echo "https://${CI_REPOSITORY_USER}:${CI_REPOSITORY_PASSWORD}@gitlab.com" > ~/.git-credentials

pull_job:
  stage: pull
  script:
    - echo "Pulling the project on the server through git"
    - git pull origin master
  only:
    - master

It works well. Now I need to execute one more command after pulling to clear the cache:

php artisan optimize

So, I add this at the end of file above:

optimize_job:
  stage: optimize
  script:
    - echo "Clearing the cache by optimize command.."
    - php artisan optimize

It throws:

.gitlab-ci.yml returns /usr/bin/bash: line 156: php: command not found error

Any idea how can I fix it?