Add showfreq.rb to SRANDMEMBER analysis tools.

utils/srandmember/showfreq.rb

+require 'redis'
+
+r = Redis.new
+r.select(9)
+r.del("myset");
+r.sadd("myset",(0..999).to_a)
+freq = {}
+100.times {
+    res = r.pipelined {
+        1000.times {
+            r.srandmember("myset")
+        }
+    }
+    res.each{|ele|
+        freq[ele] = 0 if freq[ele] == nil
+        freq[ele] += 1
+    }
+}
+
+# Print the frequency each element was yeld to process it with gnuplot
+freq.each{|item,count|
+    puts "#{item} #{count}"
+}