Merge pull request #16 from JulianHentea/54145937_about_exceptions_master.rb

Learned About Exceptions

[Delivers #54145937]
Update about_iteration.rb
Update about_iteration.rb
Update about_blocks.rb
Update about_blocks.rb
Learned about iteration
  * Inject still confuses me 
  * but I know the difference between map and   
    each