Added an ENV var to be set to an additional - optional - directory for mysql initialzition files

Author: Guy Matz

Diff for: percona-server-5.7/README.md

@@ -86,6 +86,10 @@ Set to `1` to allow the container to be started with enabled ROCKSDB engine.
 
 Set to `1` will skip starting the `mysqld` process and will run only the initialization part if MySQL was not initialized before.
 
+## `MYSQL_INIT_DB`
+
+Set to directory where initialization files reside.  This is an additional directory for initialzation, on top of the default directory, /docker-entrypoint-initdb.d
+
 # Notes, Tips, Gotchas
 
 ## Secure Container Startup

Diff for: percona-server-5.7/ps-entry.sh

@@ -202,6 +202,11 @@ if [ "$1" = 'mysqld' -a -z "$wantHelp" ]; then
 			process_init_file "$f" "${mysql[@]}"
 		done
 
+		ls $MYSQL_INIT_DIR > /dev/null
+		for f in ${MYSQL_INIT_DIR}/*; do
+			process_init_file "$f" "${mysql[@]}"
+		done
+
 		if [ ! -z "$MYSQL_ONETIME_PASSWORD" ]; then
 			"${mysql[@]}" <<-EOSQL
 				ALTER USER 'root'@'%' PASSWORD EXPIRE;