Add CLI related to channels + add comments to channels

Fixes: https://pagure.io/koji/issue/1711
Fixes: https://pagure.io/koji/issue/1849

docs/schema-upgrade-1.25-1.26.sql

@@ -0,0 +1,9 @@
+-- upgrade script to migrate the Koji database schema
+-- from version 1.25 to 1.26
+
+
+BEGIN;
+
+ALTER TABLE channels ADD COLUMN description TEXT;
+
+COMMIT;

docs/schema.sql

@@ -135,7 +135,8 @@ CREATE INDEX sessions_expired ON sessions(expired);
 -- listening to.
 CREATE TABLE channels (
 	id SERIAL NOT NULL PRIMARY KEY,
-	name VARCHAR(128) UNIQUE NOT NULL
+	name VARCHAR(128) UNIQUE NOT NULL,
+	description TEXT
 ) WITHOUT OIDS;
 
 -- create default channel