Create setting-policies-for-an-app.md

docs/en/Recipes/development/setting-policies-for-an-app.md

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+# Setting policies for an app
+
+[Policies]() are permissions granted to a VTEX IO app that allows it to execute a given set of actions once installed in an account.
+
+The next section presents a step by step on how to declare the permissions your app may need.
+
+## Step by step
+
+1. Open your app directory in your code editor.
+2. Open the `manifest.json` file and, **according to your scenario**, check the "Referencing a policy" or "Referencing a set of policies" section to declare the policies your app may need.
+3. Save your changes.
+
+### Referencing a policy
+
+For each policy, one must declare:
+
+- a `name`, which is a unique identifier of a given policy.
+- a `reason`, which may briefly describe the policy.
+
+>:warning: **Keep in mind:** The `reason` may aid the person who wants to install the app in taking the decision of installing it or not.
+
+- `attrs` (optional), which may contain the `host` and the `path` of a service's URL that needs to be called.
+
+Take the following example:
+
+```json
+"policies": [
+    {
+        "name": "example-read-write",
+        "reason": "Store the zip code of the user."
+    },
+    {
+        "name": "outbound-access",
+        "reason": "Automatically compute shipping prices for a logged user who gave us their zip code.",
+        "attrs": {
+            "host": "{example}.com",
+            "path": "/api/logistics/shipping"
+        }
+    }
+]
+```
+
+Notice that, in this example, two policies were declared:
+
+- `example-read-write`, which stores the zip code of a user.
+- `outbound-access`, which automatically computes shipping prices for a logged user who provided his zip code. Note that, in this case, attributes such as `host` and `path` are necessary to communicate with a specific logistics service.
+
+### Referencing a set of policies
+
+We also allow an app to export a `policies.json` file, containing a given set of policies. To reference one of those in your app manifest, you may set the `name` value as the app name that declared the `policies.json` followed by the policy name, as in `{account}.{app-name}@{version}:{policy-name}`.
+
+Check the example below:
+
+```json
+"policies": [
+    { "name": "vtex.app-name:catalog-proxy" }
+]
+```
+
+Notice that `catalog-proxy` is the `name` of a policy previously declared in a `policies.json` file of the `app-name` app.
+
+## Modus Operandis
+
+Once you performed the desired changes in the `policies` of your app's `manifest.json` file, a set of permissions will be granted to your app. 
+
+Therefore, the act of installing your app may consider the acceptance of those permissions.