Initialize the application passing the given group. By default, the group is :default but sprockets precompilation passes group equals to assets if initialize_on_precompile is false to avoid booting the whole app.
# File railties/lib/rails/application.rb, line 213 def initialize!(group=:default) #:nodoc: raise "Application has been already initialized." if @initialized run_initializers(group, self) @initialized = true self end