docker-compose

app:
  build: .
  command: bundle exec rails server -p 3000 -b 0.0.0.0
  environment:
    RACK_ENV: development
    RAILS_ENV: development
  ports:
    - "3000:3000"
  volumes:
    - .:/app

Dockerfile

FROM ruby:2.2 

RUN apt-get update && apt-get install -y \ 
  build-essential

RUN mkdir -p /app 
WORKDIR /app

test

$ docker-compose build
$ docker-compose run app bundle install

$ docker-compose run app bundle exec rails

bundler: command not found: rails
Install missing gem executables with 'bundle install'