Update README.md

Added some explanations to all config params

README.md

@@ -37,19 +37,30 @@ Now CouchDB takes care of the couchmagick process.
 
 ```ini
 [couchmagick]
-; Optional username and password
+; Optional username and password, used by the workers to access the database
 username = mein-user
 password = secure
-; Number of simultanous streams of changes feeds in parallel. Default is 1.
-; Increase it to the number of your databases, to get best performance.
-streams = 1
+; Number of simultaneous changes feeds in parallel. Default is 1.
+; Increase it to at least  the number of your databases, to get best performance.
+; If streams is less than the number of databases, all databases will still be queried
+; but in intervals of the changes_feed_timeout (see below). You should keep the 
+; streams parameter equal to or larger than the number of databases in the server
+; usually.
+streams = 20
 ; Concurrency level (number of simultanous convert processes per stream). Default is 1.
+; this should be set to the number of cores of your cpu for optimum performance, but
+; it really depends on the number of databases and their usage patterns.
 concurrency = 1
-; Timeout for convert process in ms. Default is 60000 (1min)
+; Timeout for a convert process in ms. Default is 60000 (1min). This should be plenty
+; for the usual image resizes, increase it if you deal with really large images and complex
+; imagemagick processing.
 convert_process_timeout = 60000
-; Timeout for changes feed in ms. Default is 10000
+; Timeout for changes feed in ms. Default is 10000. See the 'streams' parameter above
+; if you have a really large number of databases in your server and cannot afford to
+; have a changes feed open to each of them.
 changes_feed_timeout = 10000
-; Batch size. Default is 100
+; Batch size. This limits the batches the workers will take from the changes feed.
+; It basically translates to a limit parameter on the changes feed. Default is 100
 limit = 100
 ```