Update README.md

## Usage

Unzip the file and add command line configuration when running the java file group5\src\main\java\bouncingshape\MainThread.java: 

Unzip the file. This project is based on gradle. You have to install gradle here:https://gradle.org/.

./bounce --image [PATH TO IMAGE FILE] --speed [INITIAL SPEED] --dir [XX], [YY], [ZZ]

After downloading and build gradle, you can run the group5\src\main\java\bouncingshape\GUI.java. The image files are also in the group5\src\main\java\bouncingshape. For example src/main/java/bouncingshape/sphere_triangles.txt.

For example:

"./bounce --image src/main/java/bouncingshape/sphere_triangles.txt --speed 100 --dir 1, 0, 0" 

If the program runs successfully once and crash in the second time, try refresh the cache.

The program some times will crash and error "Process 'command 'C:\Program Files\Java\jdk\bin\java.exe'' finished with non-zero exit value 1 eclipse". You can try "File -> invalidate cache.. -> invalidate and restart" if you are using Intellij. This problem also sometimes exists when the input image file is too large.

## Code

 Link to the branch containing all complete: https://agile.bu.edu/gitlab/ec504/ec504_projects/group5.git