banana-bread.md: Add metric measurements

Signed-off-by: Alan Orth <alan.orth@gmail.com>

banana-bread.md

@@ -4,13 +4,13 @@ Originally from: http://www.simplyrecipes.com/recipes/banana_bread/
 ## Ingredients
 
 - 3 or 4 ripe bananas, mashed
-- 1/3 cup melted butter
-- 3/4 cup sugar
+- 1/3 cup melted butter (80 ml)
+- 3/4 cup sugar (180 ml)
 - 1 egg, beaten
 - 1 teaspoon vanilla
 - 1 teaspoon baking soda
 - Pinch of salt
-- 1 1/2 cups of all-purpose flour
+- 1 1/2 cups of all-purpose flour (375 ml)
 - Handful of walnut pieces (optional)
 - Ground flax seed (optional)