index column analysingh works for both postgres and cockroach

plugins/dbgate-plugin-postgres/src/backend/sql/indexcols.js

@@ -0,0 +1,24 @@
+module.exports = `
+    select
+        a.attname as "column_name",
+        a.attnum as "attnum",
+        a.attrelid as "oid"
+    from
+        pg_class t,
+        pg_class i,
+        pg_attribute a,
+        pg_index ix,
+        pg_namespace c
+    where
+        t.oid = ix.indrelid
+        and a.attnum = ANY(ix.indkey)
+        and a.attrelid = t.oid
+        and i.oid = ix.indexrelid
+        and t.relkind = 'r'
+        and ix.indisprimary = false
+        and t.relnamespace = c.oid
+        and c.nspname != 'pg_catalog'
+        and ('tables:' || c.nspname || '.' ||  t.relname) =OBJECT_ID_CONDITION
+    order by
+        t.relname
+`;