doc(readme): better wording and link to rollbar.com (#194)

* doc(readme): link to rollbar.com

* the Continuous Code Improvement Platform

* projects, users, and teams

* projects, users, tokens, and teams

README.md

@@ -1,11 +1,12 @@
 Terraform provider for Rollbar
 ==============================
 
-The Rollbar provider is used to interact with Rollbar resources.
+The Rollbar provider allows Terraform to control resources on
+[Rollbar.com](https://rollbar.com), the Continuous Code Improvement Platform.
 
-The provider allows you to manage your Rollbar account's projects, members, and
-teams easily. It needs to be configured with the proper credentials before it
-can be used.
+The provider allows you to manage your Rollbar projects, tokens, users, and
+teams with ease. It must be configured with the proper credentials before it can
+be used.
 
 
 Status