Update readme

Author: swissspidy

README.md

@@ -727,7 +727,7 @@ The size defaults to a human-readable number.
 
 ### wp db columns
 
-Display information about a given table.
+Displays information about a given table.
 
 ~~~
 wp db columns [<table>] [--format]
@@ -736,26 +736,50 @@ wp db columns [<table>] [--format]
 **OPTIONS**
 
 	[<table>]
-		Table name
+		Name of the database table.
 
 	[--format]
-		table, csv, json
+		Render output in a particular format.
 		---
 		default: table
 		options:
 		  - table
 		  - csv
 		  - json
+		  - yaml
+		  - csv
 		---
 
 **EXAMPLES**
 
-    $ wp db columns
-    +-------------------+------+
-    | Name              | Size |
-    +-------------------+------+
-    | wordpress_default | 6 MB |
-    +-------------------+------+
+    $ wp db columns wp_posts
+    +-----------------------+---------------------+------+-----+---------------------+----------------+
+    |         Field         |        Type         | Null | Key |       Default       |     Extra      |
+    +-----------------------+---------------------+------+-----+---------------------+----------------+
+    | ID                    | bigint(20) unsigned | NO   | PRI |                     | auto_increment |
+    | post_author           | bigint(20) unsigned | NO   | MUL | 0                   |                |
+    | post_date             | datetime            | NO   |     | 0000-00-00 00:00:00 |                |
+    | post_date_gmt         | datetime            | NO   |     | 0000-00-00 00:00:00 |                |
+    | post_content          | longtext            | NO   |     |                     |                |
+    | post_title            | text                | NO   |     |                     |                |
+    | post_excerpt          | text                | NO   |     |                     |                |
+    | post_status           | varchar(20)         | NO   |     | publish             |                |
+    | comment_status        | varchar(20)         | NO   |     | open                |                |
+    | ping_status           | varchar(20)         | NO   |     | open                |                |
+    | post_password         | varchar(255)        | NO   |     |                     |                |
+    | post_name             | varchar(200)        | NO   | MUL |                     |                |
+    | to_ping               | text                | NO   |     |                     |                |
+    | pinged                | text                | NO   |     |                     |                |
+    | post_modified         | datetime            | NO   |     | 0000-00-00 00:00:00 |                |
+    | post_modified_gmt     | datetime            | NO   |     | 0000-00-00 00:00:00 |                |
+    | post_content_filtered | longtext            | NO   |     |                     |                |
+    | post_parent           | bigint(20) unsigned | NO   | MUL | 0                   |                |
+    | guid                  | varchar(255)        | NO   |     |                     |                |
+    | menu_order            | int(11)             | NO   |     | 0                   |                |
+    | post_type             | varchar(20)         | NO   | MUL | post                |                |
+    | post_mime_type        | varchar(100)        | NO   |     |                     |                |
+    | comment_count         | bigint(20)          | NO   |     | 0                   |                |
+    +-----------------------+---------------------+------+-----+---------------------+----------------+
 
 ## Installing