Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/channels/db/migrations/mysql/000016_create_reactions.up.sql

@@ -0,0 +1,76 @@
+CREATE TABLE IF NOT EXISTS Reactions (
+    UserId varchar(26) NOT NULL,
+    PostId varchar(26) NOT NULL,
+    EmojiName varchar(64) NOT NULL,
+    CreateAt bigint(20) DEFAULT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+SET @preparedStatement = (SELECT IF(
+    (
+        SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+        WHERE table_name = 'Reactions'
+        AND table_schema = DATABASE()
+        AND column_name = 'UpdateAt'
+    ) > 0,
+    'SELECT 1',
+    'ALTER TABLE Reactions ADD COLUMN UpdateAt bigint(20);'
+));
+
+PREPARE alterIfNotExists FROM @preparedStatement;
+EXECUTE alterIfNotExists;
+DEALLOCATE PREPARE alterIfNotExists;
+
+SET @preparedStatement = (SELECT IF(
+    (
+        SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+        WHERE table_name = 'Reactions'
+        AND table_schema = DATABASE()
+        AND column_name = 'DeleteAt'
+    ) > 0,
+    'SELECT 1',
+    'ALTER TABLE Reactions ADD COLUMN DeleteAt bigint(20);'
+));
+
+PREPARE alterIfNotExists FROM @preparedStatement;
+EXECUTE alterIfNotExists;
+DEALLOCATE PREPARE alterIfNotExists;
+
+CREATE PROCEDURE AlterPrimaryKey()
+BEGIN
+    DECLARE existingPK varchar(26) default '';
+
+    SELECT IFNULL(GROUP_CONCAT(column_name ORDER BY seq_in_index), '') INTO existingPK
+    FROM information_schema.statistics
+    WHERE table_schema = DATABASE()
+    AND table_name = 'Reactions'
+    AND index_name = 'PRIMARY'
+    GROUP BY index_name;
+
+    IF existingPK != 'PostId,UserId,EmojiName' THEN
+        IF existingPk != '' THEN
+            ALTER TABLE Reactions DROP PRIMARY KEY;
+        END IF;
+
+        ALTER TABLE Reactions ADD PRIMARY KEY (PostId, UserID, EmojiName);
+    END IF;
+END;
+
+CALL AlterPrimaryKey();
+
+DROP PROCEDURE IF EXISTS AlterPrimaryKey;
+
+
+SET @preparedStatement = (SELECT IF(
+    (
+        SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+        WHERE table_name = 'Reactions'
+        AND table_schema = DATABASE()
+        AND column_name = 'RemoteId'
+    ) > 0,
+    'SELECT 1',
+    'ALTER TABLE Reactions ADD COLUMN RemoteId varchar(26);'
+));
+
+PREPARE alterIfNotExists FROM @preparedStatement;
+EXECUTE alterIfNotExists;
+DEALLOCATE PREPARE alterIfNotExists;