concurrency/generator: added generator pattern

added the generator pattern and implementation using channel

concurrency/generator.go

@@ -0,0 +1,24 @@
+package generator
+
+func Range(start int, end int, step int) chan int {
+	c := make(chan int)
+
+	go func() {
+		result := start
+		for result < end {
+			c <- result
+			result = result + step
+		}
+
+		close(c)
+	}()
+
+	return c
+}
+
+func main() {
+	// print the numbers from 3 through 47 with a step size of 2
+	for i := range Range(3, 47, 2) {
+		println(i)
+	}
+}

concurrency/generator.md

@@ -0,0 +1,7 @@
+# Generator Pattern
+
+[Generators](https://en.wikipedia.org/wiki/Generator_(computer_programming)) yields a sequence of values one at a time
+
+# Implementation and Example
+
+You can find the implementation and usage in [generator.go](generator.go)