Cannot find "concurrently" running a Docker Image - docker

Question

I am trying to create and run a Docker image of my Angular application. It works perfectly fine locally however I am having problems when it is coming to the docker run command.
My Dockerfile is:
FROM node:current
#FROM node:current-slim
#FROM node:12.13.1-alpine
WORKDIR /usr/src/app
COPY package.json .
COPY proxy.conf.json .
RUN npm install
EXPOSE 4200
CMD [ "npm", "run", "dev" ]
In my package.json the scripts are:
"dev": "concurrently \"npm start\" \"ng serve --proxy-config proxy.conf.json\""
and the two Docker commands I am running are:
docker build --tag fuel-consumption-front:0.0.0 .
docker run --publish 8000:4200 --detach --name fuel fuel-consumption-front:0.0.0
The Docker logs are saying (or this is the output on my desktop Docker application for this):
> fuel-consumption-front#0.0.0 dev /usr/src/app
> concurrently "npm start" "ng serve --proxy-config proxy.conf.json"
sh: 1: concurrently: not found
npm ERR! code ELIFECYCLE
npm ERR! syscall spawn
npm ERR! file sh
npm ERR! errno ENOENT
npm ERR! fuel-consumption-front#0.0.0 dev: `concurrently "npm start" "ng serve --proxy-config proxy.conf.json"`
npm ERR! spawn ENOENT
npm ERR!
npm ERR! Failed at the fuel-consumption-front#0.0.0 dev script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! /root/.npm/_logs/2020-03-25T15_30_19_063Z-debug.log
It is the first line that is making me think this is something to do with concurrently not being able to be run
I have tried different node images (commented out in the Dockerfile) and also npm insall -g within the Dockerfile. There is not an entry for concurrentrly in the package.json file either. All different methods are throwing up the same error
I am pretty new with Docker and was using the example from the Docker pages as a template. Their example worked perfectly fine when doing this.

Answer 1

I had more of a play with this after leaving it for a while. Turned out I didn't save my Dockerfile when I added npm install concurrently. Now the Dockerfile reads (with a few more tweaks):
FROM node:current-slim
WORKDIR /usr/src/app
COPY package.json .
COPY proxy.conf.json .
RUN npm install
RUN npm install concurrently
COPY . .
EXPOSE 4200
CMD [ "npm", "run", "dev" ]
Now onto the next issue....need to make the image smaller and it says it compiles fine in the logs but can't connect on localhost:8000 (another problem for another day!)