add a :tags command that takes you to /tags

I couldn't think of a better place, yet

static/js/command-line.js

@@ -200,6 +200,16 @@ CommandLine.registerCommand({
     },
 });
 
+CommandLine.registerCommand({
+    aliases: ["tags", "t"],
+    description: "view a list of all tags (I promise it's more interesting than you think)",
+    immediate: true,
+
+    run() {
+        window.location = `${TREEHOUSE_SITE}/tag`;
+    },
+});
+
 CommandLine.registerCommand({
     aliases: ["quit", "exit", "q", "q!", "wq", "wq!", "wqa", "wqa!", "bc", "bc!", "bca", "bca!"],
     description: "quit riki's treehouse (congration!)",