Update README.md

[Zesky665]

Updated the readme with an example of turning a list of maps into a dataframe.

[billylanchantin]

Thanks, @Zesky665! I agree this explanation could be improved.

Actually, can I ask that we expand the scope of your changes a bit? Something like this:

You can pass the data in column-wise as a map (or keyword) of series:

```elixir
name = Explorer.Series.from_list(["Everest", "K2", "Aconcagua"])
elevation = Explorer.Series.from_list([8848, 8611, 6962])
mountains = Explorer.DataFrame.new(name: name, elevation: elevation)
```

Or you can pass the data in column-wise as a map (or keyword) of lists:

```elixir
mountains = Explorer.DataFrame.new(
  name: ["Everest", "K2", "Aconcagua"],
  elevation: [8848, 8611, 6962]
)
```

Or you can pass it in row-wise as a list of maps (or keywords):

```elixir
mountains = Explorer.DataFrame.new([
  [name: "Everest", elevation: 8848],
  [name: "K2", elevation: 8611],
  [name: "Aconcagua", elevation: 6962]
])
```

All are equivalent, and your dataframe will look like this:

This way, your change and the clause that precedes will feel cohesive IMO. I leave the exact wording up to you, though.