Fix for #707

Try to replace text but skip overwritting file with pretend option

Author: scambra

lib/thor/actions/inject_into_file.rb

@@ -106,12 +106,11 @@ def say_status(behavior, warning: nil, color: nil)
       # Adds the content to the file.
       #
       def replace!(regexp, string, force)
-        return if pretend?
         content = File.read(destination)
         if force || !content.include?(replacement)
           success = content.gsub!(regexp, string)
 
-          File.open(destination, "wb") { |file| file.write(content) }
+          File.open(destination, "wb") { |file| file.write(content) } unless pretend?
           success
         end
       end