Rename SERVERS.md to SERVER_SIDE.md

It might be easier for someone to spot what this file is for when
downloading through a package manager.

Author: FagnerMartinsBrack

README.md

@@ -260,7 +260,7 @@ Cookies.withConverter({
 
 ## Server-side integration
 
-Check out the [Servers Docs](SERVERS.md)
+Check out the [Servers Docs](SERVER_SIDE.md)
 
 ## Contributing