update docs and .gitignore

.gitignore

@@ -1,13 +1,5 @@
 node_modules/
-.settings/
-.idea/
 coverage/
-docs/
 public/
 pages/
 
-ts/*.js
-ts/*.js.map
-ts/typings/
-test/result/
-

docs/index.md

@@ -0,0 +1,40 @@
+### Usage
+```javascript
+import * as gulp from 'gulp';
+import gulpFunction from 'gulp-function' // default ES6 export
+// import {forFirst, forEach, atEnd} from 'gulp-function'
+let Q = require("q");
+
+let myFunction = function (file, enc) { // file and enc are optional in case you want to modify the file object
+    let done = Q.defer();
+    console.log("Hello World!")
+    
+    // NOTE:
+    // you can use done.resolve as callback function
+    // of any async tasks within this function
+    done.resolve();
+    
+    return done.promise;
+}
+
+gulp.task('gulpTest',function() {
+    let stream = gulp.src('./mydir/*.something')
+        .pipe(gulpFunction(myFunction,'forEach')) //read the notes below
+        // .pipe(forEach(myFunction)) // if imported as >> import { forEach } from 'gulp-function' <<
+        .pipe(gulp.dest("./build/"));
+    return stream; // by returning the stream gulp knows when our task has finished.
+});
+```
+
+### Notes:
+
+* The first argument of gulpFunction can also be an **array of multiple functionnames**.
+Each function can return a promise. The pipe stop will finish when every promise is fullfilled.
+When providing an array of functions be careful with modifying the file object -> race condition
+* The second argument can be empty, it defaults to "forEach"
+* The following options are available:
+    * "forFirst" - executes when first chunk/vinylfile of the stream reaches the pipestop.
+       file is pushed further down the line when function's returned promise is fullfilled.
+    *  "forEach" - executes like "forFirst" but with every chunk/vinylfile in the stream;
+    *  "atEnd" - executes after all chunks have passed and are processed in full.
+       That means the stream's "finish" event fires **before "atLast" is executed**!!!