Fix minor grammar issues

12factor/04_external_services.md

@@ -11,8 +11,8 @@ This ensure the application is loosely coupled with the services so it can easil
 
 ## What does that mean for our application ?
 
-At this point, the only external service the application is using is MongoDB database. The loosely coupling is already done by the MONGO_URL used to pass the connection string.
+At this point, the only external service the application is using is MongoDB database. The loose coupling is already done by the MONGO_URL used to pass the connection string.
 
-If something wrong happens with our instance of MongoDB (assuming a single instance is used, which is generally a bad idea...), we can easily switch to a new instance, providing a new MONGO_URL environment variable and restart the application.
+If something wrong happens with our instance of MongoDB (assuming a single instance is used, which is generally a bad idea...), we can easily switch to a new instance, providing a new MONGO_URL environment variable and restarting the application.
 
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