moved Dockerfile to subdirectory, updated rocksdb from 3.13.1 to 4.2, and use rocksdb ppa

docker/Dockerfile

@@ -14,11 +14,12 @@ RUN apt-get update && \
 	zlib1g-dev \
 	libedit-dev
 
-# cmake and llvm ppas. then update ppas
+# cmake, llvm and rocksdb ppas. then update ppas
 RUN add-apt-repository -y "ppa:george-edison55/cmake-3.x" && \
 	add-apt-repository "deb http://llvm.org/apt/trusty/ llvm-toolchain-trusty-3.7 main" && \
+	add-apt-repository "deb http://ppa.launchpad.net/giskou/librocksdb/ubuntu trusty main" && \
 	apt-get update && \
-	apt-get install -y --force-yes cmake llvm-3.7-dev
+	apt-get install -y --force-yes cmake llvm-3.7-dev librocksdb
 
 # install evmjit
 RUN git clone https://github.com/debris/evmjit && \
@@ -26,12 +27,6 @@ RUN git clone https://github.com/debris/evmjit && \
 	mkdir build && cd build && \
 	cmake .. && make && make install && cd
 
-# install rocksdb
-RUN wget https://github.com/facebook/rocksdb/archive/rocksdb-3.13.1.tar.gz && \
-	tar -zxvf rocksdb-3.13.1.tar.gz && \
-	cd rocksdb-rocksdb-3.13.1 && \
-	make shared_lib && make install && cd
-
 # install multirust
 RUN curl -sf https://raw.githubusercontent.com/brson/multirust/master/blastoff.sh | sh -s -- --yes
 
@@ -43,6 +38,3 @@ ENV LIBRARY_PATH /usr/local/lib
 
 # show backtraces
 ENV RUST_BACKTRACE 1
-
-# run tests synchronously. Temporary workaround for evmjit cache race condition
-ENV RUST_TEST_THREADS 1