Added comments to few columns in dbversion, task and task_run

Change double quoted comments to single quoted comments

To keep consistent comment format and to prevent syntax exception on jenkins build

Make changes as per review

Made changes as per review

sql/updates/13.sql

+insert into dbversion (version, release, description)
+       values (13, now(), 'Work In Progress');
+
+-- comments for columns of table dbversion
+comment on column dbversion.version is 'SQL schema version';
+comment on column dbversion.release is 'Version deployment timestamp';
+comment on column dbversion.description is 'Version description';
+
+-- comments for columns of table task
+comment on column task.id is 'Task Identifier';
+comment on column task.type is 'References task_type table';
+comment on column task.status is 'Task status (''next_run_not_scheduled'', ''next_run_scheduled'', ''completed'', ''disabled'')';
+
+-- comments for columns of table task_run
+comment on column task_run.id is 'Task run identifier';
+comment on column task_run.task is 'References task table';
+comment on column task_run.scheduled is 'Scheduled run time for task';
+comment on column task_run.started is 'Task starting time';
+comment on column task_run.ended is 'Task ending time';

swh/scheduler/sql/30-swh-schema.sql

@@ -6,9 +6,12 @@ create table dbversion
 );
 
 comment on table dbversion is 'Schema update tracking';
+comment on column dbversion.version is 'SQL schema version';
+comment on column dbversion.release is 'Version deployment timestamp';
+comment on column dbversion.description is 'Version description';
 
 insert into dbversion (version, release, description)
-       values (12, now(), 'Work In Progress');
+       values (13, now(), 'Work In Progress');
 
 create table task_type (
   type text primary key,
@@ -80,6 +83,9 @@ comment on column task.policy is 'Whether the task is one-shot or recurring';
 comment on column task.retries_left is 'The number of "short delay" retries of the task in case of '
                                        'transient failure';
 comment on column task.priority is 'Policy of the given task';
+comment on column task.id is 'Task Identifier';
+comment on column task.type is 'References task_type table';
+comment on column task.status is 'Task status (''next_run_not_scheduled'', ''next_run_scheduled'', ''completed'', ''disabled'')';
 
 create type task_run_status as enum ('scheduled', 'started', 'eventful', 'uneventful', 'failed', 'permfailed', 'lost');
 comment on type task_run_status is 'Status of a given task run';
@@ -99,4 +105,9 @@ comment on column task_run.backend_id is 'id of the task run in the job-running
 comment on column task_run.metadata is 'Useful metadata for the given task run. '
                                        'For instance, the worker that took on the job, '
                                        'or the logs for the run.';
+comment on column task_run.id is 'Task run identifier';
+comment on column task_run.task is 'References task table';
+comment on column task_run.scheduled is 'Scheduled run time for task';
+comment on column task_run.started is 'Task starting time';
+comment on column task_run.ended is 'Task ending time';