Fix a broken URL in contributing.md (#538)

Fixed the url in contributing.md with working one.

Co-authored-by: justheuristic <justheuristic@gmail.com>

Dockerfile

@@ -9,11 +9,14 @@ RUN echo "LC_ALL=en_US.UTF-8" >> /etc/environment
 # Install packages
 RUN apt-get update && apt-get install -y --no-install-recommends --force-yes \
   build-essential \
+  curl \
   wget \
   git \
   vim \
   && apt-get clean autoclean && rm -rf /var/lib/apt/lists/{apt,dpkg,cache,log} /tmp/* /var/tmp/*
 
+RUN curl https://sh.rustup.rs -sSf | sh -s -- -y
+ENV PATH="/root/.cargo/bin:${PATH}"
 RUN wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O install_miniconda.sh && \
   bash install_miniconda.sh -b -p /opt/conda && rm install_miniconda.sh
 ENV PATH="/opt/conda/bin:${PATH}"

docs/user/contributing.md

@@ -2,7 +2,7 @@
 
 This section describes the ways to contribute to the hivemind library. For technical details of developing this library
 and getting towards merging your code in the master branch, read
-the [guidelines](https://github.com/learning-at-home/hivemind/blob/master/CONTRIBUTING.md) in our GitHub repository. In
+the [guidelines](https://github.com/learning-at-home/hivemind/blob/master/CONTRIBUTING.md#) in our GitHub repository. In
 any case, please follow the [Contributor Covenant](https://www.contributor-covenant.org/version/2/0/code_of_conduct/)
 code of conduct when discussing the library and the changes with other community members.