Add a codeowners. (#279)

Signed-off-by: Tom Wilkie <[email protected]>

Author: tomwilkie

CODEOWNERS

@@ -0,0 +1,7 @@
+# https://help.github.com/articles/about-codeowners/
+# https://git-scm.com/docs/gitignore#_pattern_format
+
+/consul*/ @grafana/cortex-team @grafana/loki-team
+/etcd-operator/ @grafana/cortex-team
+/memcached*/ @grafana/cortex-team @grafana/loki-team
+/prometheus-ksonnet/ @grafana/infra-team @grafana/cortex-team