Update D6 system

Quick update to the D6 system by adding support for single dice rolls.

fixes #230

src/dice_maiden_logic.rb

@@ -19,6 +19,7 @@ def alias_input_pass(input)
     [/\b\d+CoD9\b/i, 'CoD 9-again', /\b(\d+)CoD9\b/i, '\\1d10 ie9 t8'], # Chronicles of Darkness (9-again)
     [/\b\d+CoDR\b/i, 'CoD rote quality', /\b(\d+)CoDR\b/i, '\\1d10 r7 t8'], # Chronicles of Darkness (Rote quality, reroll all failed)
     [/\bd6s\d+\b/i, 'The D6 System', /\bd6s(\d+)\b/i, '\\1d6 + 1d6 ie'], # The D6 System
+    [/\bd6s\b/i, '1 die D6 System', /\bd6s\b/i, '\\1d6ie'], # Single die role for the D6 System
     [/\bsr\d+\b/i, 'Shadowrun', /\bsr(\d+)\b/i, '\\1d6 t5'], # Shadowrun system
     [/\b\d+d%\B/i, 'Percentile roll', /\b(\d+)d%\B/i, '\\1d100'], # Roll a d100
     [/\bsp\d+\b/i, 'Storypath', /\bsp(\d+)\b/i, 'ul \\1d10 ie10 t8'], # storypath system