Update knex.md with seed docs. (#1328)

Update knex.md with seed docs.

knex.md

@@ -69,15 +69,27 @@ See: [Update](#update-1)
 
 ### Migrations
 
-```
+```bash
 knex init
 knex migrate:make migration_name
+knex migrate:make migration_name -x ts # Generates a TypeScript migration file
 knex migrate:latest
 knex migrate:rollback
 ```
 
 See: [Migrations](#migrations-1)
 
+### Seeds
+
+```bash
+knex seed:make seed_name
+knex seed:make seed_name -x ts # Generates a TypeScript seed file
+knex seed:run # Runs all seed files
+knex seed:run --specific=seed-filename.js # Runs a specific seed file
+```
+
+See: [Seeds](http://knexjs.org/#Seeds)
+
 ## Connect
 {: .-three-column}