fix: playlists videos removal for PostgreSQL (#835)

* Fix playlists videos removal for PostgreSQL

Fixes the constraint violation error upon removing a video from a playlist with PostgreSQL

Resolves TeamPiped/Piped#2814

* Replace comment

* Show responses for the requests in api-test.sh

* Revert "Show responses for the requests in api-test.sh"

This reverts commit 29f6447.

Author: ValentinsParamonovs

src/main/resources/changelog/db.changelog-master.xml

@@ -6,4 +6,5 @@
 
     <include file="version/0-init.xml" relativeToChangelogFile="true"/>
     <include file="version/1-fix-subs.xml" relativeToChangelogFile="true"/>
+    <include file="version/2-fix-playlist-reordering-in-postgresql.xml" relativeToChangelogFile="true"/>
 </databaseChangeLog>

src/main/resources/changelog/version/2-fix-playlist-reordering-in-postgresql.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                   xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
+                   https://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
+
+    <changeSet id="2-0-postgresql" author="valentins.paramonovs" dbms="postgresql">
+        <!-- delay constraint checks until the end of the transaction to allow videos in a playlist to be reordered without worrying about the update execution order -->
+        <sql>ALTER TABLE playlists_videos_ids DROP CONSTRAINT playlists_videos_ids_pkey;</sql>
+        <sql>ALTER TABLE playlists_videos_ids ADD CONSTRAINT playlists_videos_ids_pkey PRIMARY KEY (playlist_id, videos_order) DEFERRABLE INITIALLY DEFERRED;</sql>
+        <rollback>
+            <sql>ALTER TABLE playlists_videos_ids DROP CONSTRAINT playlists_videos_ids_pkey;</sql>
+            <sql>ALTER TABLE playlists_videos_ids ADD CONSTRAINT playlists_videos_ids_pkey PRIMARY KEY (playlist_id, videos_order);</sql>
+        </rollback>
+    </changeSet>
+
+</databaseChangeLog>