CODEOWNERS: specify more precise codeowners (#5333)

.github/CODEOWNERS

@@ -1,9 +1,27 @@
 # CODEOWNERS: https://help.github.com/articles/about-codeowners/
 
-# Everything goes through Bucky, Anton, Tess. For now.
-*       @ebuchman @melekes @tessr
+# Everything goes through the following "global owners" by default. 
+# Unless a later match takes precedence, these three will be
+# requested for review when someone opens a PR. 
+# Note that the last matching pattern takes precedence, so
+# global owners are only requested if there isn't a more specific
+# codeowner specified below. For this reason, the global codeowners 
+# are often repeated in package-level definitions.
+*       @ebuchman @erikgrinaker @melekes @tessr 
+
+# Overrides for tooling packages
+.circleci/ @marbar3778  @ebuchman @erikgrinaker @melekes @tessr 
+.github/ @marbar3778 @ebuchman @erikgrinaker @melekes @tessr 
+DOCKER/ @marbar3778 @ebuchman @erikgrinaker @melekes @tessr 
+
+# Overrides for core Tendermint packages 
+abci/  @marbar3778 @ebuchman @erikgrinaker @melekes @tessr 
+evidence/ @cmwaters @ebuchman @erikgrinaker @melekes @tessr
+light/ @cmwaters @melekes @ebuchman
+
+# Overrides for docs
+*.md @marbar3778 @ebuchman @erikgrinaker @melekes @tessr  
+docs/ @marbar3778 @ebuchman @erikgrinaker @melekes @tessr 
+
+
 
-# Precious documentation
-/docs/README.md  @zramsay
-/docs/DOCS_README.md  @zramsay
-/docs/.vuepress/  @zramsay