prettifying defaults

foo.rb

# The column object we get from AR has a default value that's String
# [4] pry(#<AnnotateRb::ModelAnnotator::ColumnAnnotation::AttributesBuilder>)> rcol = @column.instance_variable_get("@column")
# => #<ActiveRecord::ConnectionAdapters::PostgreSQL::Column:0x000000010e19ea60
#  @collation=nil,
#  @comment=nil,
#  @default="0",
#  @default_function=nil,
#  @generated="",
#  @name="duration_minutes",
#  @null=true,
#  @serial=nil,
#  @sql_type_metadata=
#   #<ActiveRecord::ConnectionAdapters::SqlTypeMetadata:0x000000010e19f140
#    @limit=4,
#    @precision=nil,
#    @scale=nil,
#    @sql_type="integer",
#    @type=:integer>>

# Internally, it also is a String
# [4] pry(#<ActiveRecord::ConnectionAdapters::PostgreSQLAdapter>)> field
# => ["duration_minutes", "integer", "0", false, 23, -1, nil, nil, ""]