module Thor::Actions::ClassMethods

def add_runtime_options!


Add runtime options that help actions execution. 
def add_runtime_options!
  class_option :force, :type => :boolean, :aliases => '-f', :group => :runtime,
                       :desc => 'Overwrite files that already exist'
  class_option :pretend, :type => :boolean, :aliases => '-p', :group => :runtime,
                         :desc => 'Run but do not make any changes'
  class_option :quiet, :type => :boolean, :aliases => '-q', :group => :runtime,
                       :desc => 'Suppress status output'
  class_option :skip, :type => :boolean, :aliases => '-s', :group => :runtime,
                      :desc => 'Skip files that already exist'
end

def source_paths


inherited paths and the source root.
method responsible to gather source_paths from this current class,
Hold source paths for one Thor instance. source_paths_for_search is the 
def source_paths
  @_source_paths ||= []
end

def source_paths_for_search


3) Parents source paths
2) Source root
1) This class source paths

Returns the source paths in the following order: 
def source_paths_for_search
  paths = []
  paths += source_paths
  paths << source_root if source_root
  paths += from_superclass(:source_paths, [])
  paths
end

def source_root(path = nil)

Stores and return the source root for this class 
def source_root(path = nil)
  @_source_root = path if path
  @_source_root ||= nil
end