Update hash value in ruby on rails

We have table which stores hash data key and value as below

sr_category_id_is"=>["194", "195", "196", "197", "198", "199"]}

We need to update the value using migration.

Sample data:

facets: {"status_x_days"=>"", "sr_category_id_is"=>["194", "195", "196", "197", "198", "199"]}