Update README

Author: JeremyPlease

README.md

@@ -1,30 +1,48 @@
 # parse-files-utils
-Utilities to list and migrate Parse files
+Utilities to list and migrate Parse files.
 
-This utility will print in the terminal all the files URL's from the parse server
+This utility will do the following:
 
-This can be really useful when you migrate your files and want to move the files from the Parse S3 host to you own.
+1. Get all files across all classess in a Parse database.
+2. Print file URLs to console OR transfer to S3, GCS, or filesystem.
+3. Rename files so that [Parse Server](https://github.com/ParsePlatform/parse-server) no longer detects that they are hosted by Parse.
+4. Update MongoDB with new file names.
 
-This utility won't save the files anywhere else. You can save the results to a file or pipe the results to another program:
+#### \*WARNING\*
+As soon as this script transfers files away from Parse.com hosted files (and renames them in the database) 
+any clients that use api.parse.com will no longer be able to access the files. 
+See the section titled "5. Files" in the [Parse Migration Guide](https://parse.com/migration) 
+and Parse Server [issue #1582](https://github.com/ParsePlatform/parse-server/issues/1582).
 
-## usage
+## Installation
 
-```
-$ node index.js
-```
+1. Clone the repo: `git clone [email protected]:parse-server-modules/parse-files-utils.git`
+2. cd into repo: `cd parse-file-utils`
+3. Install dependencies: `npm install`
+
+## Usage
 
-you can optionally specify a json configuration file
+The quickest way to get started is to run `node index.js` and follow the command prompts.
 
+You can optionally specify a js/json configuration file (see [config.example.js](./config.example.js)).
 ```
-$ node index.js ./config.json
+$ node index.js config.js
 ```
 
-Example `config.json`:
-
-```
-{
-  "applicationId": "PVpAyhBmNuouwPBNksRLPVpAyhBmNuouwPBNksRL",
-  "masterKey": "DQzeY9lelKLPeWQH6zhsNUqnrudyOU07hjC6g53a",
-  "serverURL": "http://parse-server.yourdomain.com/parse"
-}
-```
+### Available configuration options
+
+* `applicationId`: Parse application id.
+* `masterKey`: Parse master key.
+* `mongoURL`: MongoDB connection url.
+* `serverURL`: The URL for the Parse server (default: http://api.parse.com/1).
+* `filesToTransfer`: Which files to transfer. Accepted options: `parseOnly`, `parseServerOnly`, `all`.
+* `renameInDatabase` (boolean): Whether or not to rename files in MongoDB.
+* `filesystemPath`: The path/directory to save files to when transfering to filesystem.
+* `aws_accessKeyId`: AWS access key id.
+* `aws_secretAccessKey`: AWS secret access key.
+* `aws_profile`: AWS credentials profile. Can be specified in lieu of `aws_accessKeyId` and `aws_secretAccessKey`.
+* `aws_bucket`: S3 bucket name.
+* `gcs_projectId`: GCS project id.
+* `gcs_keyFilename`: GCS key filename (ie. `credentials.json`).
+* `gcs_bucket`: GCS bucket name.
+* `asyncLimit`: The number of files to process at the same time (default: 5).