Mysql2 Adapter doesn't escape tenant during drop

[ghempton]

In a crunch and don't have time for a formal PR/tests, but for anyone else's reference, we fixed this with the following monkey patch:

require 'apartment/adapters/mysql2_adapter'

class Apartment::Adapters::Mysql2Adapter

  #   Drop the tenant
  #
  #   @param {String} tenant Database name
  #
  def drop(tenant)
    # Apartment.connection.drop_database   note that drop_database will not throw an exception, so manually execute
    Apartment.connection.execute("DROP DATABASE `#{environmentify(tenant)}`" )

  rescue *rescuable_exceptions
    raise DatabaseNotFound, "The tenant #{environmentify(tenant)} cannot be found"
  end

end