Quote each value in default arrays

[jmondo]

Previously, quoting an array fell back to inspect, which is ok for
strings, but not good for BigDecimals, for instance.

[jmondo]

in our project we have an order model with "individual portions" column that is an array of decimals in postgres. the default is an array with the BigDecimal 1.0 in it.

before:

#  individual_portions                        :decimal(, )      default([#<BigDecimal:7fd89b22c1a0,'0.1E1',9(18)>]), is an Array

after:

#  individual_portions                        :decimal(, )      default(["1.0"]), is an Array