Added Dockerfile to build from source

Dockerfile

+FROM ubuntu:14.04
+
+## Environment setup
+ENV HOME /root
+ENV GOPATH /root/go
+ENV PATH /go/bin:/root/go/bin:/usr/local/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
+
+RUN mkdir -p /root/go
+ENV DEBIAN_FRONTEND noninteractive
+
+## Install base dependencies
+RUN apt-get update && apt-get upgrade -y
+RUN apt-get install -y git mercurial build-essential software-properties-common pkg-config libgmp3-dev libreadline6-dev libpcre3-dev libpcre++-dev
+
+## Build and install Go
+RUN hg clone -u release https://code.google.com/p/go
+RUN cd go && hg update go1.4
+RUN cd go/src && ./all.bash && go version
+
+## Install GUI dependencies
+RUN add-apt-repository ppa:ubuntu-sdk-team/ppa -y
+RUN apt-get update -y
+RUN apt-get install -y qtbase5-private-dev qtdeclarative5-private-dev libqt5opengl5-dev
+
+## Fetch and install serpent-go
+RUN go get -v -d github.com/ethereum/serpent-go
+WORKDIR $GOPATH/src/github.com/ethereum/serpent-go
+RUN git checkout master
+RUN git submodule update --init
+RUN go install -v
+
+# Fetch and install go-ethereum
+RUN go get -v -d github.com/ethereum/go-ethereum/...
+WORKDIR $GOPATH/src/github.com/ethereum/go-ethereum
+RUN git checkout poc8
+RUN ETH_DEPS=$(go list -f '{{.Imports}} {{.TestImports}} {{.XTestImports}}' github.com/ethereum/go-ethereum/... | sed -e 's/\[//g' | sed -e 's/\]//g' | sed -e 's/C //g'); if [ "$ETH_DEPS" ]; then go get $TEST_DEPS; fi
+RUN go install -v ./cmd/ethereum
+
+# Run JSON RPC
+ENTRYPOINT ["ethereum", "-rpc=true", "-rpcport=8080"]
+EXPOSE 8080