class Rails::Railtie

def register_block_for(type, &blk)

`#each_registered_block(type, &block)`
blank and append given block to value, which will be used later in
receives an instance variable identifier, set the variable value if is 
def register_block_for(type, &blk)
  var_name = "@#{type}"
  blocks = instance_variable_defined?(var_name) ? instance_variable_get(var_name) : instance_variable_set(var_name, [])
  blocks << blk if blk
  blocks
end