Using postgres ENUM with rails yields `PG::DatatypeMismatch`

Trying to update the value of a Postgres ENUM column throws the following exception:

ActiveRecord::StatementInvalid Exception: PG::DatatypeMismatch: ERROR: column "interesting_column" is of type interesting_thing but expression is of type integer

LINE 1: UPDATE "interesting_table" SET "interesting_column" = 0, "updated_a...

HINT: You will need to rewrite or cast the expression.

InterestingTable.first.update_attributes!(normal_column: 'food')
  # => perfectly fine
InterestingTable.first.update_attributes!(interesting_column: 'foo')
  # => above exception

Here is the migration to create the table:

class CreateInterestingTables < ActiveRecord::Migration
  def up
    execute <<-SQL
      CREATE TYPE normal_thing AS ENUM ('food', 'water', 'shelter');
      CREATE TYPE interesting_thing AS ENUM ('foo', 'bar', 'baz');
    SQL

    create_table :interesting_tables do |t|
      t.column :normal_column, :normal_thing
      t.column :interesting_column, :interesting_thing
    end
  end

  def down
    drop_table :interesting_tables
    execute 'DROP TYPE normal_thing'
    execute 'DROP TYPE interesting_thing'
  end
end