initial checkin

Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>

number/semigroup.go

@@ -0,0 +1,11 @@
+package number
+
+import (
+	S "github.com/ibm/fp-go/semigroup"
+)
+
+func SemigroupSum[A int | int8 | int16 | int32 | int64 | float32 | float64 | complex64 | complex128]() S.Semigroup[A] {
+	return S.MakeSemigroup(func(first A, second A) A {
+		return first + second
+	})
+}