Function uuid_generate_v4() does not exist postgres 11
Unfortunately, I do not have much information about what your pg-migrate files look like, but you must specify the following:
pgm.createExtension('uuid-ossp', { ifNotExists: true });// andpgm.createTable('my_table', { id: { type: 'uuid', primaryKey: true, default: new PgLiteral('gen_random_uuid()') }, // ...