Add bin and edit workflow

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

@@ -0,0 +1,23 @@
+module Math
+
+  # Greatest common divisor of +m+ and +n+, +nil+ for non-positive
+  # numbers - gcd is computed by means of the Euclidian algorithm.
+  def self.gcd(m, n)
+    m = Integer(m)
+    n = Integer(n)
+    if m <= 0 || n <= 0
+      return nil
+    end
+    loop {
+      if m < n
+        m, n = n, m
+      end
+      if (l = m % n) == 0
+        break
+      end
+      m = l
+    }
+    n
+  end
+
+end