Add tasks for all the new languages

Task/Hash-join/Sidef/hash-join.sidef

@@ -0,0 +1,30 @@
+func hashJoin(table1, index1, table2, index2) {
+    var a = []
+    var h = Hash()
+
+    # hash phase
+    table1.each { |s|
+        h{s[index1]} := [] << s
+    }
+
+    # join phase
+    table2.each { |r|
+        a += h{r[index2]}.map{[_,r]}
+    }
+
+    return a
+}
+
+var t1  = [[27, "Jonah"],
+           [18, "Alan"],
+           [28, "Glory"],
+           [18, "Popeye"],
+           [28, "Alan"]]
+
+var t2  = [["Jonah", "Whales"],
+           ["Jonah", "Spiders"],
+           ["Alan", "Ghosts"],
+           ["Alan", "Zombies"],
+           ["Glory", "Buffy"]]
+
+hashJoin(t1, 1, t2, 0).each { .say }