If you aren't sure how to run a rake task, first find out first what tasks you have and it will also list the commands to run the tasks.
Run rake --tasks
on the terminal.
It will list the tasks like the following:
rake gobble:dev:prime
rake gobble:dev:reset_number_of_kits
rake gobble:dev:scrub_prod_data
You can then run your task with: rake gobble:dev:prime
as listed.