Add topic for "psr-7"

Author: shaedrich

topics/psr-7/index.md

@@ -0,0 +1,9 @@
+---
+display_name: "PSR-7: HTTP message interfaces"
+short_description: PSR-7 is a set of common interfaces representing HTTP messages, and URIs.
+topic: psr-7
+related: rfc-7230, rfc-7231, rfc-3986, http-message, psr-17
+url: https://www.php-fig.org/psr/psr-7/
+created_by: Matthew Weier O'Phinney
+---
+PSR-7 is a set of common interfaces defined by PHP Framework Interop Group. These interfaces are representing HTTP messages, and URIs for use when communicating trough HTTP.