update some implementations

ts/smartgit.commit.ts

@@ -1,7 +1,15 @@
-import plugins = require("./smartgit.plugins");
+import * as plugins from "./smartgit.plugins";
+import * as helpers from "./smartgit.helpers";
 
-export = function(pathArg:string,commitMessage:string) {
+export let commit = (dirPathArg:string,commitMessage:string) => {
     let done = plugins.Q.defer();
+    if(!plugins.smartfile.fs.isDirectory(plugins.path.join(dirPathArg,".git"))){
+        plugins.beautylog.error("smartgit.commit expects a valid git directory");
+        done.reject();
+        return done.promise;
+    };
+    // if everything is all right proceed
+    plugins.shelljs.exec(`git commit -m "${commitMessage}"`);
     done.resolve();
     return done.promise;
 };