Add bin and edit workflow

bin/gems/facets-3.1.0/lib/standard/facets/math/mean.rb

@@ -0,0 +1,16 @@
+require  'facets/math/sum'
+
+module Math
+
+  # Mean average.
+  def self.mean(array, &blk)
+    s = array.size
+    return 0.0 if s == 0
+    sum(array, &blk) / s
+  end
+
+  class << self
+    alias_method :mean_average, :mean
+  end
+
+end