Add explanation of the discovery to help/readme.

Author: Nils Dijk

README.md

@@ -28,6 +28,38 @@ Command-line tools for Ringpop
 
     -h, --help     output usage information
     -V, --version  output the version number
+
+  Discovery:
+
+    Most of the commands can discover the ring via
+    a discoverUri like this: 'ringpop://127.0.0.1:3000'.
+    If no protocol is specified 'ringpop://' will be
+    used.
+
+    Supported protocols are:
+
+     - ringpop://
+       Discover the ring by connecting to a host of
+       the ring.
+
+       Example: ringpop://127.0.0.1:3000
+
+     - file://
+       Discover the ring by reading a json file
+       containing an array of host:port combinations
+
+       Example: file:///absolute/path/to/file
+       Example: file://./relative/path
+       File content: ["127.0.0.1:3000"]
+
+     - hyperbahn://
+       Discover the ring by querying hyperbahn for
+       the members of a service. When no hyperbahn
+       ip and port are given 127.0.0.1:21300 will be
+       used.
+
+       Example: hyperbahn:///ringpop
+       Example: hyperbahn://hyperbahn-ip:port/ringpop
 ```
 
 ## Tests

ringpop-admin.js

@@ -38,6 +38,40 @@ function main() {
         .command('status', 'Status of members in ring')
         .command('partitions', 'Show partition information of a ring')
         .command('top', 'General membership information')
+        .on('--help', function onHelp() {
+            console.log('  Discovery:');
+            console.log('');
+            console.log('    Most of the commands can discover the ring via');
+            console.log('    a discoverUri like this: \'ringpop://127.0.0.1:3000\'.');
+            console.log('    If no protocol is specified \'ringpop://\' will be');
+            console.log('    used.');
+            console.log('');
+            console.log('    Supported protocols are:');
+            console.log('');
+            console.log('     - ringpop://');
+            console.log('       Discover the ring by connecting to a host of');
+            console.log('       the ring.');
+            console.log('');
+            console.log('       Example: ringpop://127.0.0.1:3000');
+            console.log('');
+            console.log('     - file://');
+            console.log('       Discover the ring by reading a json file');
+            console.log('       containing an array of host:port combinations');
+            console.log('');
+            console.log('       Example: file:///absolute/path/to/file');
+            console.log('       Example: file://./relative/path');
+            console.log('       File content: ["127.0.0.1:3000"]');
+            console.log('');
+            console.log('     - hyperbahn://');
+            console.log('       Discover the ring by querying hyperbahn for');
+            console.log('       the members of a service. When no hyperbahn');
+            console.log('       ip and port are given 127.0.0.1:21300 will be');
+            console.log('       used.');
+            console.log('');
+            console.log('       Example: hyperbahn:///ringpop');
+            console.log('       Example: hyperbahn://hyperbahn-ip:port/ringpop');
+            console.log('');
+        })
         .parse(process.argv);
 }
 

tests/ringpop-admin.t

@@ -33,3 +33,35 @@ Help:
       -h, --help     output usage information
       -V, --version  output the version number
 
+    Discovery:
+  
+      Most of the commands can discover the ring via
+      a discoverUri like this: 'ringpop://127.0.0.1:3000'.
+      If no protocol is specified 'ringpop://' will be
+      used.
+  
+      Supported protocols are:
+  
+       - ringpop://
+         Discover the ring by connecting to a host of
+         the ring.
+  
+         Example: ringpop://127.0.0.1:3000
+  
+       - file://
+         Discover the ring by reading a json file
+         containing an array of host:port combinations
+  
+         Example: file:///absolute/path/to/file
+         Example: file://./relative/path
+         File content: ["127.0.0.1:3000"]
+  
+       - hyperbahn://
+         Discover the ring by querying hyperbahn for
+         the members of a service. When no hyperbahn
+         ip and port are given 127.0.0.1:21300 will be
+         used.
+  
+         Example: hyperbahn:///ringpop
+         Example: hyperbahn://hyperbahn-ip:port/ringpop
+