roman-numerals: Added template to the stub file (#579)
roman-numerals: Added template to the stub file (#579)

* roman-numerals: Added template to the stub file

* roman-numerals: Replaced i32 type with u32 type in 'From' trait template implementation

exercism/xrust,petertseng/exercism-rust,petertseng/exercism-rust,exercism/xrust,petertseng/exercism-rust