feat(docs): improve documentation of pgres

Author: veritem

README.md

@@ -74,7 +74,7 @@ let body = resp
 use postgrest::Postgrest;
 use dotenv;
 
-dotenv::dotenv().ok(); 
+dotenv::dotenv().ok();
 
 let client = Postgrest::new("https://your.supabase.endpoint/rest/v1")
     .insert_header(
@@ -90,6 +90,30 @@ let body = resp
     .await?;
 ```
 
+if you have RLS enabled you're required to add an extra header for this libary to  function correctly.
+
+```rust
+use postgrest::Postgrest;
+use dotenv;
+
+dotenv::dotenv().ok();
+
+let client = Postgrest::new("https://your.supabase.endpoint/rest/v1/")
+    .insert_header(
+        "apikey",
+        dotenv::var("SUPABASE_PUBLIC_API_KEY").unwrap())
+    .insert_header("Authorization", format!("Bearer {}", SERVICE_KEY))
+
+let resp = client
+    .from("your_table")
+    .select("*")
+    .execute()
+    .await?;
+let body = resp
+    .text()
+    .await?;
+```
+
 ### Building Queries
 
 These examples assume you've already initialized the client.  The methods `.from()` and `.rpc()` initalizes the query builder inside the client.