Add pager support for output.

TODO

@@ -1,6 +1,6 @@
 # vi: ft=vimwiki
 * [ ] Fix: SELECT id, <tab>  FROM django_migrations; - Auto-completion for the second column name is broken. Find the last keyword and use it for completion.
-* [ ] Use a pager to display the output. (Check Click's document).
+* [ ] Bottom status bar is cut-off in half pane. Figure out how to fix that.
 * [ ] Default host should not be set to localhost. Since it causes problems in IPv6 machines. Need to research this one further.
 * [ ] Column completion for nested sql.
 * [ ] Add JOIN to the list of keywords and provide proper autocompletion for it. 
@@ -27,6 +27,7 @@
 * [ ] New Feature List - Write the current version to config file. At launch if the version has changed, display the changelog between the two versions.
 * [o] Separate the column completions to be table specific. (SELECT, INSERT, UPDATE)
 * [X] Write a doc about how to run it in develop mode. (pip install -e .)
+* [X] Use a pager to display the output. (Check Click's document).
 * [X] Column completion for simple SELECT.
 * [X] Column completion for simple INSERT.
 * [X] Column completion for simple UPDATE.

pgcli/main.py

@@ -87,11 +87,13 @@ def cli(database, user, password, host, port):
                 raise Exit
             try:
                 res = pgexecute.run(document.text)
+                output = []
                 for rows, headers, status in res:
                     if rows:
-                        print(tabulate(rows, headers, tablefmt='psql'))
+                        output.append(tabulate(rows, headers, tablefmt='psql'))
                     if status:  # Only print the status if it's not None.
-                        print(status)
+                        output.append(status)
+                    click.echo_via_pager('\n'.join(output))
             except Exception as e:
                 click.secho(e.message, err=True, fg='red')