add a few example scripts

scripts/counter.lua

@@ -0,0 +1,14 @@
+-- example dynamic request script which demonstrates changing
+-- the request path and a header for each request
+-------------------------------------------------------------
+-- NOTE: each wrk thread has an independent Lua scripting
+-- context and thus there will be one counter per thread
+
+counter = 0
+
+request = function()
+   path = "/" .. counter
+   wrk.headers["X-Counter"] = counter
+   counter = counter + 1
+   return wrk.format(nil, path)
+end