I wrote this as prep for a talk about JSON datatype and PLV8: https://speakerdeck.com/selenamarie/schema-liberation-with-json-and-plv8-and-postgres

liberate.sql

CREATE SCHEMA liberated;
 
CREATE OR REPLACE FUNCTION public.liberate()                                    
 RETURNS boolean                                                                
 LANGUAGE plv8                                                                  
AS $function$                                                                   

  var tables = plv8.execute(
    "select relname FROM pg_catalog.pg_class"
    + " c LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace"
    + " where relkind = 'r' and n.nspname = 'public'");
  
  var tablesLength = tables.length;
  for (var i = 0; i < tablesLength; i++) {                                     
    plv8.elog(NOTICE, tables[i]['relname']);                                    
    var code = "create table liberated." 
      + tables[i]['relname'] 
      + " as ( select row_to_json("
      +  tables[i]['relname'] 
      + ") as liberated_json "
      + "from select * from " 
      + tables[i]['relname']
      + ")" ;
    plv8.execute(code);                                                         
  }                                                                         
  return 1;                                                                     

$function$;