Updating 'Executing the migrations' sub-section.

README.md

@@ -64,6 +64,8 @@ In this command:
 ```bash
 migrate -path=./migrations -database=$GREENLIGHT_DB_DSN up
 ```
+---
+
 Note: You may get the error: **error: pq: permission denied for schema public...** when running this command. It's because Postgres might revoke the **CREATE** permission from all users except a database ownser. 
 
 To get around this, set the database owner to the **greenlight** user: 
@@ -76,6 +78,22 @@ If that still doesn't work, try explicitly granting the **CREATE** privileges to
 GRANT CREATE ON DATABASE greenlight TO greelight;
 ```
 
+---
+
+The **schema_migrations** table is automatically generated by the **migrate** tool and used to keep track of which migrations have been applied. 
+
+```
+greenlight => SELECT * FROM schema_migrations;
+
+version | dirty
+-----------------
+      2 | f
+```
+
+The **version** column here indicates that our migration files up (and including) number **2** in the sequence have been executed against the database. The value of **dirty** column is **false**, which indicates that the migration files were cleanly executed _without any errors_ and the SQL statements they contain were successfully applied in _full_.
+
+You can run the **\d** meta command on the **movies** table to see the structure of the table and confirm the **CHECK** constraints were created correctly.
+
 ## Additional Information
 
 ### How different Go Types are encoded