update installation from INSTALL.md

Installation.md

@@ -118,6 +118,7 @@ For reference or if you want to create the table schema for yourself (replace
 `prefix_` with your own table prefix and create the table schema with phpMyAdmin
 or the MYSQL console):
 
+```sql
 CREATE TABLE prefix_paste (
     dataid CHAR(16) NOT NULL,
     data BLOB,
@@ -147,3 +148,6 @@ or the MYSQL console):
     id CHAR(16) NOT NULL, value TEXT, PRIMARY KEY (id)
 );
 INSERT INTO prefix_config VALUES('VERSION', '1.1');
+```
+
+In PostgreSQL the attachment column needs to be TEXT and not BLOB or MEDIUMBLOB.