updates all product READMEs with links to the PHP sample docs (GoogleCloudPlatform#919)

Author: bshaffer

bigquery/api/README.md

@@ -2,7 +2,10 @@
 
 ## Description
 
-All code in the `snippets` directory demonstrate how to invoke Google BigQuery from PHP.
+All code in the `snippets` directory demonstrate how to invoke
+[Google BigQuery][bigquery] from PHP.
+
+[bigquery]: https://cloud.google.com/bigquery/docs/quickstarts/quickstart-client-libraries
 
 ## Build and Run
 1.  **Enable APIs** - [Enable the BigQuery API](https://console.cloud.google.com/flows/enableapi?apiid=bigquery)

bigtable/README.md

@@ -2,8 +2,13 @@
 
 ## Description
 
+These samples show how to use the
+[Cloud Bigtable API][bigtable] from PHP.
+
 All code in the `src` directory demonstrates how to connect to Cloud Bigtable and run some basic operations to create instance, create cluster, delete instance and delete cluster.
 
+[bigtable]: https://cloud.google.com/bigtable/docs/reference/libraries
+
 ## Build and Run
 1.  **Enable APIs** - [Enable the Bigtable API](https://console.cloud.google.com/flows/enableapi?apiid=bigtable)
     and create a new project or select an existing project.

datastore/api/README.md

@@ -1,7 +1,9 @@
 # Cloud Datastore code snippets
 
-This code samples are intended to be in the following document:
-https://cloud.google.com/datastore/docs/
+These samples show how to use the [Datastore API][datastore]
+from PHP.
+
+[datastore]: https://cloud.google.com/datastore/docs/reference/libraries
 
 The code is using
 [Google Cloud Client Library for PHP](https://googlecloudplatform.github.io/google-cloud-php/#/).

debugger/README.md

@@ -3,7 +3,9 @@
 ## Description
 
 This simple [Silex][silex] application demonstrates how to
-install and run the Stackdriver Debugger Agent for PHP.
+install and run the [Stackdriver Debugger Agent][debugger] for PHP.
+
+[debugger]: https://cloud.google.com/debugger/docs/setup/php
 
 ## Build and Run
 

dialogflow/README.md

@@ -11,7 +11,7 @@ This command-line application demonstrates how to invoke Dialogflow
 API from PHP.
 
 ## Before you begin
-1. Follow the first 2 steps of [this quickstart](https://cloud.google.com/dialogflow-enterprise/docs/quickstart).
+1. Follow the first 2 steps of [this quickstart](https://cloud.google.com/dialogflow-enterprise/docs/quickstart-api).
 Feel free to stop after you've created an agent.
 
 2. This sample comes with a [sample agent](https://github.com/GoogleCloudPlatform/php-docs-samples/blob/master/dialogflow/resources/RoomReservation.zip) which you can use to try the samples with. Follow the instructions on [this page](https://dialogflow.com/docs/best-practices/import-export-for-versions) to import the agent from the [console](https://console.dialogflow.com/api-client).

dlp/README.md

@@ -7,8 +7,10 @@
 
 ## Description
 
-This simple command-line application demonstrates how to invoke Google
-DLP API from PHP.
+This simple command-line application demonstrates how to invoke
+[Google DLP API][dlp-api] from PHP.
+
+[dlp-api]: https://cloud.google.com/dlp/docs/libraries
 
 ## Build and Run
 1.  **Enable APIs** - [Enable the DLP API](

error_reporting/README.md

@@ -5,8 +5,15 @@
 [shell_img]: http://gstatic.com/cloudssh/images/open-btn.svg
 [shell_link]: https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googlecloudplatform/php-docs-samples&page=editor&working_dir=error_reporting
 
-`quickstart.php` and `error_reporting.php` are simple command-line programs to demonstrate logging
-exceptions, errors, and PHP fatral errors to Stackdriver Error Reporting.
+
+This directory contains samples for setting up and using
+[Stackdriver Error Reporting][error-reporting] for PHP.
+
+[error-reporting]: https://cloud.google.com/error-reporting/docs/setup/php
+
+`quickstart.php` and `src/report_error.php` are simple command-line programs to
+demonstrate logging exceptions, errors, and PHP fatral errors to
+Stackdriver Error Reporting.
 
 # Installation
 

firestore/README.md

@@ -2,7 +2,7 @@
 
 These samples show how to use the [Google Cloud Firestore API][cloud-firestore-api] to store and query data.
 
-[cloud-firestore-api]: http://cloud.google.com/cloud-firestore
+[cloud-firestore-api]: https://cloud.google.com/firestore/docs/quickstart-servers
 
 ## Setup
 

jobs/README.md

@@ -2,8 +2,10 @@
 
 ## Description
 
-These samples show how to use the [Google Cloud Job Discovery API]
-(https://cloud.google.com/job-discovery/).
+These samples show how to use the [Google Cloud Job Discovery API][job-discovery]
+from PHP.
+
+[job-discovery]: https://cloud.google.com/talent-solution/job-search/v2/docs/libraries
 
 ## Build and Run
 1.  **Enable APIs** - [Enable the Job Discovery API](https://console.cloud.google.com/flows/enableapi?apiid=jobs.googleapis.com)

kms/README.md

@@ -7,7 +7,8 @@
 
 ## Description
 
-These samples show how to use the [Google Cloud KMS API](https://cloud.google.com/kms/).
+These samples show how to use the
+[Google Cloud KMS API](https://cloud.google.com/kms/docs/reference/libraries) from PHP.
 
 ## Build and Run
 1.  **Enable APIs** - [Enable the KMS API](https://console.cloud.google.com/flows/enableapi?apiid=cloudkms.googleapis.com)