Add creation_time and modification_time DB columns

This will permits to know if non-updated data exist.

lib/Hea/Library.pm

@@ -25,8 +25,8 @@ sub create {
 
     my $dbh = Hea::Dbh::dbh;
     my $sql = q{
-        INSERT INTO library (library_id, name, url, library_type, country)
-        VALUES (?, ?, ?, ?, ?)
+        INSERT INTO library (library_id, name, url, library_type, country, creation_time)
+        VALUES (?, ?, ?, ?, ?, NOW())
     };
 
     $library->{type} ||= '';

schema.sql

@@ -5,7 +5,9 @@ CREATE TABLE library (
     kohaversion VARCHAR(255) NULL DEFAULT NULL,
     url VARCHAR(255) NULL DEFAULT NULL,
     library_type VARCHAR(255) NOT NULL DEFAULT '',
-    country VARCHAR(255) NOT NULL DEFAULT ''
+    country VARCHAR(255) NOT NULL DEFAULT '',
+    creation_time TIMESTAMP NOT NULL,
+    modification_time TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 DROP TABLE IF EXISTS volumetry;