-[DOC] psl command : add description

README.md

@@ -39,6 +39,7 @@ and provides helpers to run (and replay) migrations until it works.
     * [Command ``upgrade`` (BETA)](#command-upgrade)
     * [Command ``generate-module-analysis`` (BETA)](#command-generate-module-analysis)
     * [Command ``estimate-workload`` (BETA)](#command-estimate-workload)
+    * [Command ``psql``](#command-psql)
 
 <a name="installation"/>
 
@@ -365,3 +366,72 @@ the work to do for the migration.
   renaming or merging of modules)
 - check that the analysis and migration have been done for the official
   modules present in odoo/odoo
+
+<a name="command-psql"/>
+
+## Command: ``psql``
+
+**Prerequites:** init
+
+```
+odoo-openupgrade-wizard psql
+    --database DB_NAME
+    --command "SQL_REQUEST"
+```
+
+Execute an SQL Request on the target database.
+
+**Optional arguments**
+
+* If no ``database`` is provided, default ``postgres`` database will be used. exemple:
+
+```
+odoo-openupgrade-wizard psql --command "\l";
+```
+Result:
+```
+                              List of databases
+    Name    | Owner | Encoding |  Collate   |   Ctype    | Access privileges
+------------+-------+----------+------------+------------+-------------------
+ postgres   | odoo  | UTF8     | en_US.utf8 | en_US.utf8 |
+ template0  | odoo  | UTF8     | en_US.utf8 | en_US.utf8 | =c/odoo          +
+            |       |          |            |            | odoo=CTc/odoo
+ template1  | odoo  | UTF8     | en_US.utf8 | en_US.utf8 | =c/odoo          +
+            |       |          |            |            | odoo=CTc/odoo
+ test_psql  | odoo  | UTF8     | en_US.utf8 | en_US.utf8 |
+
+```
+
+* if you execute request that return long result, you can choose to select ``pager`` or ``-no-pager``
+  option to display the result via the click function ``echo_via_pager``.
+  (see : https://click.palletsprojects.com/en/8.1.x/utils/#pager-support)
+
+Note : Pager is enabled by default.
+
+
+* you can pass extra psql arguments inline.
+
+```
+odoo-openupgrade-wizard psql
+    --database=test_psql
+    --command "select id, name from res_partner where name ilike '%admin%';"
+    -H
+```
+Result:
+```
+<table border="1">
+  <tr>
+    <th align="center">id</th>
+    <th align="center">name</th>
+  </tr>
+  <tr valign="top">
+    <td align="right">3</td>
+    <td align="left">Administrator</td>
+  </tr>
+</table>
+<p>(1 row)<br />
+</p>
+
+```
+
+See all the options here https://www.postgresql.org/docs/current/app-psql.html