ataru can handle multiple files and test methods are named after md files

- Now, ataru can handle multiple files:

```bash
$ ataru my_file.md my_file_2.md
```

- Test method names contain the filename of the markdown file.
**tl;dr**

Adding global methods is always bad practice™.

**The long version**

But as always problems tend to be more complex than a simple answer that fits in a tweet ;-) But let me first explain what "global" means:

As you may already have heard in Ruby everything is an object. Even if you just write something without an enclosing class there is still an object around. To illustrate this type `self.class` into an IRB session. You will get `Object` as an answer. Adding methods to this object (which is called `main` by the way) will not make those methods available everywhere but only in the scope of this specific object:

```ruby
# will be added to 'main'
def foo
  puts "bar"
end

foo # will print 'hello'

class Bar
  def bar
    # will raise an error
    foo
  end
end
```

Adding methods that are truly available everywhere is a bit more complicated (and should be again avoided).

To come back to the beginning: There are some rare cases where it is useful to add global methods. In most cases it is not. This entire topic leads to some nice things about creating DSLs and using closures. But I will not go down this rabbit hole with you, at least not now ;-)