add ps tips

SysadminTips.page

@@ -1,3 +1,9 @@
+```ps``` with long user fields (here 20).
+
+```
+ps axo user:20,pid,pcpu,pmem,vsz,rss,tty,stat,start,time,comm
+```
+
 WTF is happening in apache (or other)? Let's strace all apache processes.  
 ```
 # strace -p $(ps auwwwx | grep apache | tr -s '\t' ' ' | cut -d' ' -f2 | tr '\n' ' ' | sed 's/ / -p /g') -p 9999