Add upgrade guide, CHANGELOG entry for 2.0.0

Author: aaron-lane

CHANGELOG.md

@@ -7,6 +7,11 @@ project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+## [2.0.0] - 2019-09-26
+
+2.0.0 is a backward incompatible release. Review the
+[upgrade guide](docs/upgrading_to_sql_db_2.0.0.md) for more information.
+
 ### Added
 
 - `peering_completed` marker to postgresql module [#43]
@@ -19,7 +24,8 @@ project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 
-- The network reference in the `private_service_access` module uses the   self link. [#61]
+- The network reference in the `private_service_access` module uses the
+  self link. [#61]
 
 ## [1.2.0] - 2019-07-30
 
@@ -33,7 +39,8 @@ project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [1.0.0] - 2019-02-14
 
-[Unreleased]: https://github.com/terraform-google-modules/terraform-google-sql-db/compare/v1.2.0...HEAD
+[Unreleased]: https://github.com/terraform-google-modules/terraform-google-sql-db/compare/v2.0.0...HEAD
+[2.0.0]: https://github.com/terraform-google-modules/terraform-google-sql-db/compare/v1.2.0...v2.0.0
 [1.2.0]: https://github.com/terraform-google-modules/terraform-google-sql-db/compare/1.1.2...v1.2.0
 [1.1.2]: https://github.com/terraform-google-modules/terraform-google-sql-db/compare/1.1.1...1.1.2
 [1.1.1]: https://github.com/terraform-google-modules/terraform-google-sql-db/compare/1.1.0...1.1.1

docs/upgrading_to_sql_db_2.0.0.md

@@ -0,0 +1,65 @@
+# Upgrading to SQL DB 2.0.0
+
+The 2.0.0 release of SQL DB is a backward incompatible release. This
+incompatibility affects any configuration which uses the root module.
+
+## Instructions
+
+Prior to the 1.1.0 release, the root module was the only mechanism to
+configure databases:
+
+```hcl
+module "sql_db_mysql" {
+  source  = "GoogleCloudPlatform/sql-db/google"
+  version = "1.0.0"
+
+  database_version = "MYSQL_5_6"
+  name             = "mysql-example"
+  project          = "example-project"
+  region           = "us-central1"
+}
+
+module "sql_db_postgresql" {
+  source  = "GoogleCloudPlatform/sql-db/google"
+  version = "1.0.0"
+
+  database_version = "POSTGRES_9_6"
+  name             = "postgresql-examlpe"
+  project          = "example-project"
+  region           = "us-central1"
+}
+```
+
+With the 1.1.0 release, submodules were added for each type of
+database. As of the 2.0.0 release, the root module has been removed so
+the submodules must be used:
+
+```diff
+ module "sql_db_mysql" {
+-  source  = "GoogleCloudPlatform/sql-db/google"
++  source  = "GoogleCloudPlatform/sql-db/google//modules/mysql"
+-  version = "1.0.0"
++  version = "~> 2.0"
+
+   database_version = "MYSQL_5_6"
+   name             = "mysql-example"
+-  project          = "example-project"
++  project_id       = "example-project"
+   region           = "us-central1"
++  zone             = "us-central1-a"
+ }
+
+ module "sql_db_postgresql" {
+-  source  = "GoogleCloudPlatform/sql-db/google"
++  source  = "GoogleCloudPlatform/sql-db/google//modules/postgresql"
+-  version = "1.0.0"
++  version = "~> 2.0"
+
+   database_version = "POSTGRES_9_6"
+   name             = "postgresql-example"
+-  project          = "example-project"
++  project_id       = "example-project"
+   region           = "us-central1"
++  zone             = "us-central1-a"
+ }
+```