Update MAINTAINERS, add OWNERS

The OWNERS file allows gerrit to automatically CC the owners on a review
when it's pushed, removing the need to add maintainers manually.

Eventually the MAINTAINERS file will be deprecated. For now keep both
until it's removed project-wide.

Replace IRC with Discord since the community doesn't use IRC anymore.
Remove Ratan, he is no longer working with IBM.
Update discord name for Gunnar, Lei, and Jayanth.

Change-Id: Id62bad573059dd58226cd90a40b4fe77952edce1
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 3afd661..6de7495 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14,7 +14,7 @@
 
     Section entries are structured according to the following scheme:
 
-    X:  NAME <EMAIL_USERNAME@DOMAIN> <IRC_USERNAME!>
+    X:  NAME <EMAIL_USERNAME@DOMAIN> <DISCORD_USERNAME!>
     X:  ...
     .
     .
@@ -24,10 +24,10 @@
     organization; FILE_PATH is a file path within the repository, possibly with
     wildcards; X is a tag of one of the following types:
 
-    M:  Denotes maintainer; has fields NAME <EMAIL_USERNAME@DOMAIN> <IRC_USERNAME!>;
+    M:  Denotes maintainer; has fields NAME <EMAIL_USERNAME@DOMAIN> <DISCORD_USERNAME!>;
         if omitted from an entry, assume one of the maintainers from the
         MAINTAINERS entry.
-    R:  Denotes reviewer; has fields NAME <EMAIL_USERNAME@DOMAIN> <IRC_USERNAME!>;
+    R:  Denotes reviewer; has fields NAME <EMAIL_USERNAME@DOMAIN> <DISCORD_USERNAME!>;
         these people are to be added as reviewers for a change matching the repo
         path.
     F:  Denotes forked from an external repository; has fields URL.
@@ -43,7 +43,6 @@
 -------------------------
 
 M:  Adriana Kobylak <anoo@us.ibm.com> <anoo!>
-M:  Gunnar Mills <gmills@linux.vnet.ibm.com> <gunnarm!>
-M:  Lei Yu <mine260309@gmail.com>
-R:  Ratan Gupta <ratagupt@linux.vnet.ibm.com> <rgupta!>
-R:  Jayanth Othayoth <ojayanth@in.ibm.com> <jayanth!>
+M:  Gunnar Mills <gmills@linux.vnet.ibm.com> <GunnarM!>
+M:  Lei Yu <mine260309@gmail.com> <LeiYU!>
+R:  Jayanth Othayoth <ojayanth@in.ibm.com> <Jayanth!>