Docker Readme update

Author: markus-perl

.dockerignore

@@ -0,0 +1,2 @@
+packages/
+workspace/

README.md

@@ -82,11 +82,20 @@ This command downloads the build script and automatically starts the build proce
 
 ### Run with Docker
 
+#### Default - Without CUDA
 ```bash
 git clone https://github.com/markus-perl/ffmpeg-build-script.git
 cd ffmpeg-build-script
 docker build --tag=ffmpeg .
-docker run  ffmpeg -i http://files.coconut.co.s3.amazonaws.com/test.mp4 -f webm -c:v libvpx -c:a libvorbis - > /tmp/test.mp4
+docker run ffmpeg -i https://files.coconut.co.s3.amazonaws.com/test.mp4 -f webm -c:v libvpx -c:a libvorbis - > /tmp/test.mp4
+```
+
+#### With CUDA
+```bash
+git clone https://github.com/markus-perl/ffmpeg-build-script.git
+cd ffmpeg-build-script
+docker build --tag=ffmpeg-cuda -f cuda-ubuntu.dockerfile .
+docker run ffmpeg-cuda -i https://files.coconut.co.s3.amazonaws.com/test.mp4 -f webm -c:v libvpx -c:a libvorbis - > /tmp/test.mp4
 ```
 
 ### Common installation

build-ffmpeg

@@ -6,11 +6,9 @@ VERSION=1.16
 CWD=$(pwd)
 PACKAGES="$CWD/packages"
 WORKSPACE="$CWD/workspace"
-CC=clang
 CFLAGS="-I$WORKSPACE/include"
 LDFLAGS="-L$WORKSPACE/lib"
 EXTRALIBS="-lpthread -lm"
-FFMPEG_OPTS=()
 CONFIGURE_OPTIONS=()
 
 # Speed up the process