updates docs for data aws_eip filter

website/docs/d/eip.html.markdown

@@ -18,6 +18,7 @@ public IP as an input variable and needs to determine the other.
 The following example shows how one might accept a public IP as a variable
 and use this data source to obtain the allocation ID when using an VPC EIP.
 
+### ip or id
 ```hcl
 variable "instance_id" {}
 variable "public_ip" {}
@@ -32,6 +33,35 @@ resource "aws_eip_association" "proxy_eip" {
 }
 ```
 
+### filter
+
+```hcl
+variable "instance_id" {}
+
+resource "aws_eip" "proxy_ip" {
+  vpc = true
+
+  tags {
+      Name = "proxy"
+    }
+}
+
+data "aws_eip" "by_filter" {
+  filter {
+    name   = "tag:Name"
+    values = ["${aws_eip.test.tags.Name}"]
+  }
+}
+
+resource "aws_eip_association" "proxy_eip" {
+  instance_id   = "${var.instance_id}"
+  allocation_id = "${data.aws_eip.proxy_ip.id}"
+}
+
+```
+
+~> **NOTE:** if using `data "aws_eip"` on a none pre exsiting EIP, ensure you reference the tag of the EIP by interpolation as shown in the example.
+
 Classic EIP's do not have an allocation_id, only use `public_ip` in the `data "aws_eip"` block.
 
 ## Argument Reference
@@ -44,6 +74,12 @@ Elastic IP whose data will be exported as attributes.
 
 * `public_ip` - (Optional) The public IP of the specific EIP to retrieve.
 
+* `filter` - (Optional) One or more name/value pairs to use as filters. There are
+several valid keys, for a full reference, check out
+[describe-addresses in the AWS CLI reference][1].
+
+~> **NOTE:** `filter` cannot be used when `id` or `public_ip` is being used.
+
 ## Attributes Reference
 
 All of the argument attributes are also exported as result attributes. This