for PM-1298 we updated the tc format for containers to allow for mount keyword

e.g
cont centos-pegasus{
     type "singularity"

     # URL to image in a docker hub or a url to an existing docker
     # file exported as a tar file
     #image "gsiftp://bamboo.isi.edu//lfs1/scratch/vahi/docker/centos-base.tar"
     image "docker:///rynge/montage:latest"

     # optional site attribute to tell pegasus which site tar file
     # exists. useful for handling file URL's correctly
     image_site "local"
  
     # a url to an existing docker file to build container image from scratch
     dockerfile "/URL"

     #mount information
     mount "/Volumes/Work/lfs1:/shared-data/:ro"
     mount "/data1:/shared-data1"

     # specify env profile via env option do docker run
     profile env "JAVA_HOME" "/opt/java/1.6"
     profile env "KARAN" "VAHI"
}