Support passing an array of columns

app/models/concerns/ignorable_columns.rb

@@ -8,9 +8,9 @@ module IgnorableColumns
     #
     # Indicate the earliest date and release we can stop ignoring the column with +remove_after+ (a date string) and +remove_with+ (a release)
     def ignore_columns(*columns, remove_after:, remove_with:)
-      raise 'Please indicate when we can stop ignoring columns with remove_after, example: ignore_columns(:name, remove_after: \'2019-12-01\', remove_with: \'12.6\')' unless remove_after && remove_with
+      raise ArgumentError, 'Please indicate when we can stop ignoring columns with remove_after, example: ignore_columns(:name, remove_after: \'2019-12-01\', remove_with: \'12.6\')' unless remove_after && remove_with
 
-      self.ignored_columns += columns
+      self.ignored_columns += columns.flatten
     end
 
     alias_method :ignore_column, :ignore_columns

spec/models/concerns/ignorable_columns_spec.rb

@@ -3,22 +3,32 @@
 require 'spec_helper'
 
 describe IgnorableColumns do
-  class User < ApplicationRecord
-    include IgnorableColumns
+  let(:record_class) do
+    Class.new(ApplicationRecord) do
+      include IgnorableColumns
+    end
   end
 
+  subject { record_class }
+
   it 'adds columns to ignored_columns' do
     expect do
-      User.ignore_columns(:name, :created_at, remove_after: '2019-12-01', remove_with: '12.6')
-    end.to change { User.ignored_columns }.from([]).to(%w(name created_at))
+      subject.ignore_columns(:name, :created_at, remove_after: '2019-12-01', remove_with: '12.6')
+    end.to change { subject.ignored_columns }.from([]).to(%w(name created_at))
+  end
+
+  it 'adds columns to ignored_columns (array version)' do
+    expect do
+      subject.ignore_columns(%i[name created_at], remove_after: '2019-12-01', remove_with: '12.6')
+    end.to change { subject.ignored_columns }.from([]).to(%w(name created_at))
   end
 
   it 'requires remove_after attribute to be set' do
-    expect { User.ignore_columns(:name, remove_after: nil, remove_with: 12.6) }.to raise_error
+    expect { subject.ignore_columns(:name, remove_after: nil, remove_with: 12.6) }.to raise_error(ArgumentError, /Please indicate/)
   end
 
   it 'requires remove_with attribute to be set' do
-    expect { User.ignore_columns(:name, remove_after: '2019-12-01', remove_with: nil) }.to raise_error
+    expect { subject.ignore_columns(:name, remove_after: '2019-12-01', remove_with: nil) }.to raise_error(ArgumentError, /Please indicate/)
   end
 
 end
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