bt: Update README

bt/README.adoc

@@ -182,8 +182,11 @@ If pre-apply checks are enabled in the config file, they can be disabled for the
 
 Multiple terraform config profiles can be defined.
 By default, the `default` profile is used.
+The default profile can be overriden with `config.default_terraform_profile` in the config file.
 
 To use a different profile, use the `--profile` option or export the `BT_TERRAFORM_PROFILE` environment variable.
+The environment variable can also be overridden to read an existing one in the environment.
+For example, set `config.terraform_profile_env_var` to `AWS_PROFILE` and name your terraform profiles the same way you name your AWS profiles.
 
 Each profile will have its own `TF_DATA_DIR` and the terraform data will be saved under `.terraform-<profile>/`.
 This allows to work with multiple profiles pointing to different backends under the same workspace directory without conflicts.

bt/changelog.adoc

@@ -2,34 +2,7 @@
 
 == v0.3.0: Breaking changes
 
-* Terraform config has been updated to support multiple profiles.
-
-Wrap the terraform config under the `default` profile to get similar behaviour.
-
-[source, diff]
-----
-  terraform: {
-+ 	default: {
-  		binary_name: "terraform"
-  		init: {
-  			backend_config: ["backend.tfvars"]
-  		}
-  		plan: {
-  			var_file: ["~/auth.tfvars"]
-  		}
-  		workspaces: {
-  			enabled: true
-  			dir: "envs"
-  		}
-  		pre_apply_checks: {
-  			enabled: true
-  			commands: [
-  				{name: "conftest", command: ["conftest", "test", "$TERRAFORM_JSON_PLAN"]},
-  			]
-  		}
-+ 	}
-  }
-----
+Terraform config has been updated to support multiple profiles.
 
 Additionally, the terraform data is no longer saved at the default `.terraform/` dir but has been changed to follow the format `.terraform-<profile>/`.