Filled in readme

README.md

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 # rack-profiler
 [![Build Status](https://travis-ci.org/iainbeeston/rack-profiler.svg)](https://travis-ci.org/iainbeeston/rack-profiler)
 
-This is my attempt to make a rack middleware that profiles memory usage in rails, with the aim of detecting memory leaks.
+This is my attempt to make a rack middleware that profiles memory usage in rails (or any rack-based app), with the aim of detecting memory leaks. After *every* request it takes a dump of the objectspace and saves it to a data store of your choice\*.
+
+This project was heavily inspired by blog posts by [@samsaffron](http://samsaffron.com/archive/2015/03/31/debugging-memory-leaks-in-ruby) and [@wagenet](http://blog.skylight.io/hunting-for-leaks-in-ruby/).
+
+\* Any object supporting the ~[]=~ method can be used as a data-store. I recommend [Moneta](http://github.com/minad/moneta), which has support for Redis and Amazon S3.
+
+## Getting Started
+
+After installing the gem, insert rack-profiler into your middleware stack:
+
+~~~
+config.middleware.insert_after ActionDispatch::Static, Rack::Profiler, store: Moneta.new(:Redis)
+~~~
+
+I'd recommend installing rack-profiler as low as you can in your stack. Preferably only requests that hit your own application code should be profiled.
+
+## Warnings
+
+*DO NOT USE THIS IN PRODUCTION* (it's *VERY* slow - I'd recommend running it on a close-copy of production instead)
+
+Every objectspace dump is unique to a particular ruby process. Make sure your server is only running a single worker when profiling.
+
+I've found that with unicorn, requests will usually time-out when using rack-profiler. Try increasing the ~timeout~ value in unicorn.rb.
+
+## How to find memory leaks
+
+Right now this bit is manual. rack-profiler will give you the objectspace for a running app. I'd recommend taking the objectspace dumps for several successive requests and looking for objects that aren't garbage collected, as @wagenet did in his [post on the Skylight blog](http://blog.skylight.io/hunting-for-leaks-in-ruby/).