Use underscores instead of dashes in Terraform file names (#746)

docs/infra/cloud-access-control.md

@@ -4,4 +4,4 @@ GitHub Actions needs permissions to create, modify, and destroy resources in the
 
 ## Adding/removing permissions from GitHub Actions
 
-To add or remove permissions from the CI/CD role, update the list of AWS services that GitHub Actions has access to, defined in the project-config module in [project-config/aws-services.tf](/infra/project-config/aws-services.tf)
+To add or remove permissions from the CI/CD role, update the list of AWS services that GitHub Actions has access to, defined in the project-config module in [project-config/aws_services.tf](/infra/project-config/aws_services.tf)

docs/infra/environment-variables-and-secrets.md

@@ -8,10 +8,10 @@ Applications may need application specific configuration as environment variable
 
 > ⚠️ Note: Do not put sensitive information such as credentials as regular environment variables. The method described in this section will embed the environment variables and their values in the ECS task definition's container definitions, so anyone with access to view the task definition will be able to see the values of the environment variables. For configuring secrets, see the section below on [Secrets](#secrets)
 
-Environment variables are defined in the `app-config` module in the [environment-variables.tf file](/infra/app/app-config/env-config/environment-variables.tf). Modify the `default_extra_environment_variables` map to define extra environment variables specific to the application. Map keys define the environment variable name, and values define the default value for the variable across application environments. For example:
+Environment variables are defined in the `app-config` module in the [environment_variables.tf file](/infra/app/app-config/env-config/environment_variables.tf). Modify the `default_extra_environment_variables` map to define extra environment variables specific to the application. Map keys define the environment variable name, and values define the default value for the variable across application environments. For example:
 
 ```terraform
-# environment-variables.tf
+# environment_variables.tf
 
 locals {
   default_extra_environment_variables = {
@@ -40,10 +40,10 @@ module "dev_config" {
 
 Secrets are a specific category of environment variables that need to be handled sensitively. Examples of secrets are authentication credentials such as API keys for external services. Secrets first need to be stored in AWS SSM Parameter Store as a `SecureString`. This section then describes how to make those secrets accessible to the ECS task as environment variables through the `secrets` configuration in the container definition (see AWS documentation on [retrieving Secrets Manager secrets through environment variables](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/secrets-envvar-secrets-manager.html)).
 
-Secrets are defined in the same file that non-sensitive environment variables are defined, in the `app-config` module in the [environment-variables.tf file](/infra/app/app-config/env-config/environment-variables.tf). Modify the `secrets` map to define the secrets that the application will have access to. For each secret, the map key defines the environment variable name. The `manage_method` property, which can be set to `"generated"` or `"manual"`, defines whether or not to generate a random secret or to reference an existing secret that was manually created and stored into AWS SSM. The `secret_store_name` property defines the SSM parameter name that stores the secret value. If `manage_method = "generated"`, then `secret_store_name` is where terraform will store the secret. If `manage_method = "manual"`, then `secret_store_name` is where terraform will look for the existing secret. For example:
+Secrets are defined in the same file that non-sensitive environment variables are defined, in the `app-config` module in the [environment_variables.tf file](/infra/app/app-config/env-config/environment_variables.tf). Modify the `secrets` map to define the secrets that the application will have access to. For each secret, the map key defines the environment variable name. The `manage_method` property, which can be set to `"generated"` or `"manual"`, defines whether or not to generate a random secret or to reference an existing secret that was manually created and stored into AWS SSM. The `secret_store_name` property defines the SSM parameter name that stores the secret value. If `manage_method = "generated"`, then `secret_store_name` is where terraform will store the secret. If `manage_method = "manual"`, then `secret_store_name` is where terraform will look for the existing secret. For example:
 
 ```terraform
-# environment-variables.tf
+# environment_variables.tf
 
 locals {
   secrets = {

docs/infra/style-guide.md

@@ -26,6 +26,7 @@ Here are some exceptions (and additions) to Hashicorp's Terraform style guide.
 - Use module names based on the logical function of the module rather than the underlying proprietary service used for implementing the module. For example, use "database" instead of "rds", or "storage" instead of "s3".
 - Organize resources according to the infrastructure layers described in [module architecture](/docs/infra/module-architecture.md).
 - [Use shared configuration](/docs/infra/module-dependencies.md) instead of the [tfe_outputs data source](https://registry.terraform.io/providers/hashicorp/tfe/latest/docs/data-sources/outputs) to share state between two state files.
+- Use underscores instead of dashes in file names and module names.
 
 #### Variables