Merge pull request #7 from ifilot/develop

Improving documentation and adding CI

.github/workflows/build.yml

@@ -0,0 +1,21 @@
+name: build
+
+on:
+  push:
+    branches: [ "master", "develop" ]
+  pull_request:
+    branches: [ "master", "develop" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Install dependencies
+      run: sudo apt install -y build-essential cmake libboost-all-dev pkg-config libeigen3-dev libpng-dev libtclap-dev
+    - name: Configure CMake
+      run: mkdir build && cd build && cmake ../src
+    - name: Build
+      run: cd build && make -j3

README.md

@@ -1,14 +1,33 @@
 # DFTCXX
 
-DFTCXX calculates the electronic structure of simple molecules within the framework of Density Functional Theory (DFT) at the LDA level of theory. It is mainly written for educational purposes. The source code has been documented (i.e. commented) relatively extensively to provide students the opportunity to read and understand the algorithm.
+[![Build](https://github.com/ifilot/dftcxx/actions/workflows/build.yml/badge.svg)](https://github.com/ifilot/dftcxx/actions/workflows/build.yml)
+
+DFTCXX calculates the electronic structure of simple molecules within the
+framework of Density Functional Theory (DFT) at the LDA level of theory. It is
+mainly written for educational purposes. The source code has been documented
+(i.e. commented) relatively extensively to provide students the opportunity to
+read and understand the algorithm.
+
+> **Note**: Want to know more about electronic structure calculations? Have a look at my
+>  [free lecture book](https://ifilot.pages.tue.nl/elements-of-electronic-structure-theory/).
+
 
 ## Compilation
 
 DFTCXX depends on a couple of libraries, which are normally directly available by your favorite package manager.
 
-* Boost
-* TCLAP
-* Eigen3
+* [Boost](https://www.boost.org/)
+* [TCLAP](https://tclap.sourceforge.net/)
+* [Eigen3](https://eigen.tuxfamily.org/index.php?title=Main_Page)
+* [libPNG](http://www.libpng.org/pub/png/libpng.html)
+
+To ensure you have the right packages on a (Debian-type) of operating system,
+you can run the following
+
+```
+sudo apt install build-essential cmake libboost-all-dev pkg-config libeigen3-dev \
+libpng-dev libtclap-dev
+```
 
 To compile the program:
 ```