Dockerfile build output 2

docker build -t currency_converter .
Sending build context to Docker daemon  53.67MB
Step 1/12 : FROM ubuntu:18.04
 ---> cd6d8154f1e1
Step 2/12 : WORKDIR /app
 ---> Using cache
 ---> 61e96da3f784
Step 3/12 : COPY /scripts /styles index.html currency_converter.cpp /app/
 ---> Using cache
 ---> c1ce2b77d342
Step 4/12 : RUN apt-get update   && apt-get install -y git                         g++                         build-essential                         make                         wget                         cmake
 ---> Using cache
 ---> 49023be84dbb
Step 5/12 : RUN wget https://dl.bintray.com/boostorg/release/1.68.0/source/boost_1_68_0.tar.bz2     && tar -xjf boost_1_68_0.tar.bz2     && rm -rf boost_1_68_0.tar.bz2     && cd boost_1_68_0     && ./bootstrap.sh     && ./b2 install
 ---> Using cache
 ---> 4e1f671775c2
Step 6/12 : RUN git clone https://github.com/flexferrum/jinja2cpp     && cd jinja2cpp     && git submodule -q update --init     && mkdir build     && cd build     && cmake .. -DCMAKE_INSTALL_PREFIX=../install     && cmake --build . --target all
 ---> Using cache
 ---> 131134c1e70d
Step 7/12 : RUN git clone https://github.com/nlohmann/json
 ---> Using cache
 ---> de420b7b12b8
Step 8/12 : RUN g++ -std=c++14 -Wall -pedantic -I app/jinja2cpp/install/include -I app/json/include -I app/json/single_include -I /usr/local/include/ -I app/jinja2cpp/thirdparty/nonstd/value-ptr-lite/include currency_converter.cpp -L app/jinja2cpp/install/lib/static -ljinja2cpp -L usr/local/lib/stage/lib/ -lboost_system -lpthread -o currency_converter
 ---> Running in bfb27a00d9c8
currency_converter.cpp:29:10: fatal error: nlohmann/json.hpp: No such file or directory
 #include <nlohmann/json.hpp>
          ^~~~~~~~~~~~~~~~~~~
compilation terminated.