Circle CI

You need to mention ruby version with browser support in the config.yml of CircleCI like this:

version: 2
jobs:
  build:
    working_directory: ~/project
    docker:
      # Browser support ruby versions
      - image: circleci/ruby:2.5.1-node-browsers
        environment:
          PGHOST: localhost
          PGUSER: user
          RAILS_ENV: test
      - image: postgres:9.5
        environment:
          POSTGRES_USER: project
          POSTGRES_DB: project_test
          POSTGRES_PASSWORD: ""

List of available ruby versions for Circle CI are mentioned here.