Source command in dockerfile

Hi,

I am working to build an image from a Docker file. In the normal way (in the ubuntu OS) for some of the software I needed to add something like in following to the bashrc file:

source <Path to FairRoot Installation>/bin/FairRootConfig.sh

How can I do the same thing when I am building a docker image?
I could not find in the ENV documentation for that.

Greets,
Maisam