Helper function to style as Markdown table

[TylerRick]

For those of us who are already using this gem and don't want to install yet another dependency like markdown-tables just to get a more concise API for generating Markdown tables.

Thanks to this library's configurability, you can already format your tables as Markdown format:

markdown_style = {
  border_top:    false,
  border_bottom: false,
  border_x:      "-",
  border_y:      "|",
  border_i:      "|"
}
puts Terminal::Table.new(headings: ['heading A', 'heading B'], rows: [['a', 'b'], ['a', 'b']], style: markdown_style)
| heading A | heading B |
|-----------|-----------|
| a         | b         |
| a         | b         |

But it would be nice if we end-users didn't have to copy and paste that big markdown_style hash every place we wanted to output a table in Markdown format.

How about something like:

Terminal::Table.new(...).as_markdown

that would automatically add style: markdown_style for you?

(In the future, we might consider making it do other things, too, like optionally escaping cell content if it contained any text that might be accidentally interpreted as Markdown format.)

(See also #106)

[nanobowers]

@nateberkopec I think this can be closed - fixed as part of #113