Readonly Access still writing into database

[maloneyl]

I followed the Readonly Access example in the readme and found that updates still managed to be written:

[9] pry(main)> customer.first_name = "Wheeeee"
=> "Wheeeee"
[10] pry(main)> customer.save

From: /Users/xxxxxxx/Development/xxxxxxxx/config/initializers/arproxy.rb @ line 7 Readonly#execute:

    2: def execute(sql, name=nil)
    3:   if sql =~ /\s*(SELECT|SET|SHOW|DESCRIBE)\b/
    4:     super sql, name
    5:   else
    6:     binding.pry
 => 7:     Rails.logger.warn "#{name} (BLOCKED) #{sql}"
    8:   end
    9: end

[3] pry(#<Readonly>)> sql
=> "BEGIN"
[4] pry(#<Readonly>)> c
 (BLOCKED) BEGIN
  SQL (1.3ms)  UPDATE "customers" SET "first_name" = $1, "updated_at" = $2 WHERE "customers"."id" = $3  [["first_name", "Wheeeee"], ["updated_at", "2016-03-04 15:57:59.788986"], ["id", "f86d3094-a36f-499b-92ee-a78a76168750"]]

From: /Users/xxxxxxx/Development/xxxxxxxx/config/initializers/arproxy.rb @ line 7 Readonly#execute:

    2: def execute(sql, name=nil)
    3:   if sql =~ /\s*(SELECT|SET|SHOW|DESCRIBE)\b/
    4:     super sql, name
    5:   else
    6:     binding.pry
 => 7:     Rails.logger.warn "#{name} (BLOCKED) #{sql}"
    8:   end
    9: end

[4] pry(#<Readonly>)> sql
=> "COMMIT"
[5] pry(#<Readonly>)> c
 (BLOCKED) COMMIT
=> true

Any pointers how I could make this truly read-only? I'm using the PostgreSQLAdapter instead of MySQL as you have in your example, if that makes any difference. Thanks!