Merge branch 'refs/heads/develop' into feature/form_error_msgs

Conflicts:
	system/language/english/form_validation_lang.php
	user_guide_src/source/libraries/form_validation.rst

Signed-off-by: Eric Roberts <eric@cryode.com>

1 files changed, 159 insertions, 1 deletions

diff --git a/user_guide_src/source/libraries/migration.rst b/user_guide_src/source/libraries/migration.rst
index 5192f1f29..1a73fb78d 100644
--- a/user_guide_src/source/libraries/migration.rst
+++ b/user_guide_src/source/libraries/migration.rst
@@ -2,4 +2,162 @@
 Migrations Class
 ################
 
-Coming soon.
\ No newline at end of file
+Migrations are a convenient way for you to alter your database in a 
+structured and organized manner. You could edit fragments of SQL by hand 
+but you would then be responsible for telling other developers that they 
+need to go and run them. You would also have to keep track of which changes 
+need to be run against the production machines next time you deploy.
+
+The database table **migration** tracks which migrations have already been 
+run so all you have to do is update your application files and 
+call **$this->migrate->current()** to work out which migrations should be run. 
+The current version is found in **config/migration.php**.
+
+********************
+Migration file names
+********************
+
+Each Migration is run in numeric order forward or backwards depending on the
+method taken. Two numbering styles are available:
+
+* **Sequential:** each migration is numbered in sequence, starting with **001**.
+  Each number must be three digits, and there must not be any gaps in the
+  sequence. (This was the numbering scheme prior to CodeIgniter 3.0.)
+* **Timestamp:** each migration is numbered using the timestamp when the migration
+  was created, in **YYYYMMDDHHIISS** format (e.g. **20121031100537**). This
+  helps prevent numbering conflicts when working in a team environment, and is
+  the preferred scheme in CodeIgniter 3.0 and later.
+
+The desired style may be selected using the **$config['migration_type']**
+setting in your **migration.php** config file.
+
+Regardless of which numbering style you choose to use, prefix your migration
+files with the migration number followed by an underscore and a descriptive
+name for the migration. For example:
+
+* **001_add_blog.php** (sequential numbering)
+* **20121031100537_add_blog.php** (timestamp numbering)
+
+******************
+Create a Migration
+******************
+	
+This will be the first migration for a new site which has a blog. All 
+migrations go in the folder **application/migrations/** and have names such 
+as **20121031100537_add_blog.php**.::
+
+	<?php
+
+	defined('BASEPATH') OR exit('No direct script access allowed');
+
+	class Migration_Add_blog extends CI_Migration {
+
+		public function up()
+		{
+			$this->dbforge->add_field(array(
+				'blog_id' => array(
+					'type' => 'INT',
+					'constraint' => 5,
+					'unsigned' => TRUE,
+					'auto_increment' => TRUE
+				),
+				'blog_title' => array(
+					'type' => 'VARCHAR',
+					'constraint' => '100',
+				),
+				'blog_description' => array(
+					'type' => 'TEXT',
+					'null' => TRUE,
+				),
+			));
+			$this->dbforge->add_key('blog_id', TRUE);
+			$this->dbforge->create_table('blog');
+		}
+
+		public function down()
+		{
+			$this->dbforge->drop_table('blog');
+		}
+	}
+
+Then in **application/config/migration.php** set **$config['migration_version'] = 1;**.
+
+*************
+Usage Example
+*************
+
+In this example some simple code is placed in **application/controllers/migrate.php** 
+to update the schema.::
+
+	<?php
+	
+	class Migrate extends CI_Controller
+	{
+	    public function index()
+	    {
+	    	$this->load->library('migration');
+	    	
+	    	if ($this->migration->current() === FALSE)
+	    	{
+	    		show_error($this->migration->error_string());
+	    	}
+	    }
+	}
+
+******************
+Function Reference
+******************
+
+$this->migration->current()
+============================
+
+The current migration is whatever is set for **$config['migration_version']** in 
+**application/config/migration.php**.
+
+$this->migration->error_string()
+=================================
+
+This returns a string of errors while performing a migration.
+
+$this->migration->find_migrations()
+====================================
+
+An array of migration filenames are returned that are found in the **migration_path** 
+property.
+
+$this->migration->latest()
+===========================
+
+This works much the same way as current() but instead of looking for 
+the **$config['migration_version']** the Migration class will use the very 
+newest migration found in the filesystem.
+
+$this->migration->version()
+============================
+
+Version can be used to roll back changes or step forwards programmatically to 
+specific versions. It works just like current but ignores **$config['migration_version']**.::
+
+	$this->load->library('migration');
+
+	$this->migration->version(5);
+
+*********************
+Migration Preferences
+*********************
+
+The following is a table of all the config options for migrations.
+
+========================== ====================== ========================== =============================================
+Preference                 Default                Options                    Description
+========================== ====================== ========================== =============================================
+**migration_enabled**      FALSE                  TRUE / FALSE               Enable or disable migrations.
+**migration_path**         APPPATH.'migrations/'  None                       The path to your migrations folder.
+**migration_version**      0                      None                       The current version your database should use.
+**migration_table**        migrations             None                       The table name for storing the schema
+                                                                             version number.
+**migration_auto_latest**  FALSE                  TRUE / FALSE               Enable or disable automatically 
+                                                                             running migrations.
+**migration_type**        'timestamp'            'timestamp' / 'sequential' The type of numeric identifier used to name
+                                                                             migration files.
+========================== ====================== ========================== =============================================