When you build a docker image, you copy all your runtime dependencies (`node_modules/`) and build artifacts into the image. When you push a deployment you are deploying that static image with the dependencies baked in, instead of trying to install the dependencies at startup.
When you build a docker image, you copy all your runtime dependencies (`node_modules/`) and build artifacts into the image. When you push a deployment you are deploying that static image with the dependencies baked in, instead of trying to install the dependencies at startup.