chore: add script for a quick integration test

Summary:
This is just a little script that will run a search and print out the timings
for each of the searches that ivy will preform.

For example running

```
nvim -l ./scripts/integration.lua /path/to/repo test 2> /dev/null
```

will output

```
t       0.074737
te      0.016494
tes     0.018898
test    0.017214
```

Test Plan:
Does not really require testing, this is a little helper script for
development. If it does not work on another machine then we can cross that
bridge when we come to it.

Reviewers: AdeAttwood

Reviewed By: AdeAttwood

Differential Revision: https://ph.baln.co.uk/D2

scripts/integration.lua

@@ -0,0 +1,30 @@
+vim.opt.rtp:append(vim.fn.getcwd())
+
+local ivy = require "ivy"
+local prompt = require "ivy.prompt"
+require "plugin.ivy"
+
+if #vim.v.argv ~= 5 then
+  print "[ERROR] Expected 5 arguments"
+  print "    Usage: nvim -l ./scripts/integration.lua <directory> <search>"
+
+  return
+end
+
+ivy.setup()
+
+vim.fn.chdir(vim.v.argv[4])
+print("Working in " .. vim.fn.getcwd())
+
+vim.cmd "IvyFd"
+
+for _, value in pairs(vim.split(vim.v.argv[5], "")) do
+  local start_time = os.clock()
+
+  vim.ivy.input(value)
+  vim.wait(0)
+
+  local running_time = os.clock() - start_time
+
+  io.stdout:write(prompt.text() .. "\t" .. running_time .. "\n")
+end