diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..924011e
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,10 @@
+# Database
+DB_ROOT_USERNAME=agapay
+DB_ROOT_PASSWORD=payments4all
+DB_PORT=5433
+DATABASE_URL='postgresql://agapay:payments4all@db:5433/agapay?connect_timeout=300'
+
+# Agapay
+INCREASE_SANDBOX=true
+INCREASE_API_KEY={REPLACE_ME}
+BANK_ENTITY={REPLACE_ME}
diff --git a/README.md b/README.md
index 0010023..1d55317 100644
--- a/README.md
+++ b/README.md
@@ -87,6 +87,14 @@ make
 make test
 ```
 
+### Configure environment variables
+
+Copy the `.env.example` file to `.env` and update the values as needed.
+
+```bash
+cp .env.example .env
+```
+
 ### Run locally
 
 First run the following command to spin up the docker containers:
diff --git a/prisma/ERD.md b/prisma/ERD.md
index e02df7e..5b15c04 100644
--- a/prisma/ERD.md
+++ b/prisma/ERD.md
@@ -72,6 +72,14 @@ erDiagram
     BigInt user_id FK
     DateTime created_at
 }
+"payment_intent" {
+    BigInt id PK
+    BigInt amount
+    String chariot_id "nullable"
+    String recipient_id FK
+    BigInt user_id FK
+    DateTime created_at
+}
 "transfer" {
     BigInt id PK
     BigInt amount
@@ -98,6 +106,7 @@ erDiagram
     BigInt id PK
     String account_number
     String routing_number
+    payment_rail preferred_payment_rail "nullable"
     bank_address_status status
     DateTime updated_at
 }
@@ -113,6 +122,8 @@ erDiagram
 "payment" }|--|| "recipient" : recipient
 "payment" }o--|| "idempotency_key" : idempotency_key
 "payment" }|--|| "user" : user
+"payment_intent" }|--|| "recipient" : recipient
+"payment_intent" }|--|| "user" : user
 "transfer" }|--|| "account" : account
 "transfer" }o--|| "idempotency_key" : idempotency_key
 "transfer" }|--|| "user" : user
@@ -198,6 +209,16 @@ erDiagram
   - `user_id`: 
   - `created_at`: 
 
+### `payment_intent`
+
+**Properties**
+  - `id`: 
+  - `amount`: 
+  - `chariot_id`: 
+  - `recipient_id`: 
+  - `user_id`: 
+  - `created_at`: 
+
 ### `transfer`
 
 **Properties**
@@ -230,5 +251,6 @@ erDiagram
   - `id`: 
   - `account_number`: 
   - `routing_number`: 
+  - `preferred_payment_rail`: 
   - `status`: 
   - `updated_at`: 
\ No newline at end of file
diff --git a/schema.prisma b/schema.prisma
index 3a87cce..393f76e 100644
--- a/schema.prisma
+++ b/schema.prisma
@@ -203,6 +203,7 @@ model payment {
 
 // payment_intent represents a payment intent from an account to a recipient
 // this is used to track offline payments that are not processed through the API
+// TODO: this is not currently used and needs some more thought
 model payment_intent {
   // the unique identifier for the payment intent
   id           BigInt    @id @default(autoincrement()) @db.BigInt
@@ -217,7 +218,11 @@ model payment_intent {
   user_id      BigInt    @db.BigInt
   user         user      @relation(fields: [user_id], references: [id], onDelete: Restrict, onUpdate: Cascade, map: "fk_payment_intent_user")
   // the time the intent was created
-  created_at         DateTime         @default(now()) @db.Timestamptz(6)
+  created_at   DateTime  @default(now()) @db.Timestamptz(6)
+
+  @@index([chariot_id], map: "idx_payment_intent_chariot_id")
+  @@index([recipient_id], map: "idx_payment_intent_recipient_id")
+  @@index([user_id], map: "idx_payment_intent_user_id")
 }
 
 // transfer represents a transfer of funds into an account