Simplify and Improve readability on some conditions

I changed some conditions to improve readability.

Example:
```ruby
 def xpto(param)
  if param
    do_something
    do_something_again
    do_something_again_and_again
  end
end
````
To
```ruby
def xpto(param)
  unless param
  do_something
  do_something_again
  do_something_again_and_again
end
```