Add comments to Node.gitignore

Node.gitignore

@@ -1,14 +1,25 @@
-lib-cov
-*.seed
+# Semi-general patterns
+## Logs
+logs
 *.log
+
+## Runtime data
+pids
+*.pid
+*.seed
+
+## Run / build output
+results
 *.csv
 *.dat
 *.out
-*.pid
 *.gz
 
-pids
-logs
-results
+# JS-specific patterns
+## Directory for files generated by jscoverage/JSCover
+lib-cov
 
+# Node-specific patterns
+## You may want to comment this out in certain scenarios:
+## see http://www.futurealoof.com/posts/nodemodules-in-git.html
 node_modules