chore: Move README.* to root

Author: krlmlr

.Rbuildignore

@@ -7,3 +7,4 @@
 ^igraphdata\.Rproj$
 ^\.Rproj\.user$
 ^\.github$
+^README\.Rmd$

inst/README.Rmd README.Rmd

@@ -0,0 +1,43 @@
+<!-- README.md is generated from README.Rmd. Please edit that file -->
+
+# Data sets for the igraph R package
+
+[![Linux build status](https://travis-ci.org/igraph/igraphdata.png)](https://travis-ci.org/igraph/igraphdata) [![Windows build status](https://ci.appveyor.com/api/projects/status/6wov9hh8oprrpkhs?svg=true)](https://ci.appveyor.com/project/gaborcsardi/igraphdata)
+
+This is a data R package, that contains network data sets, to be used with the igraph R package.
+
+## Installation
+
+From CRAN:
+
+<pre class='chroma'>
+<span><span class='nf'><a href='https://rdrr.io/r/utils/install.packages.html'>install.packages</a></span><span class='o'>(</span><span class='s'>"igraphdata"</span><span class='o'>)</span></span></pre>
+
+You can install the development version from Github, using the [devtools package](https://github.com/hadley/devtools):
+
+<pre class='chroma'>
+<span><span class='nf'>devtools</span><span class='nf'>::</span><span class='nf'><a href='https://remotes.r-lib.org/reference/install_github.html'>install_github</a></span><span class='o'>(</span><span class='s'>"igraph/igraphdata"</span><span class='o'>)</span></span></pre>
+
+## Usage
+
+<pre class='chroma'>
+<span><span class='kr'><a href='https://rdrr.io/r/base/library.html'>library</a></span><span class='o'>(</span><span class='nv'><a href='http://igraph.org'>igraphdata</a></span><span class='o'>)</span></span>
+<span><span class='nf'><a href='https://rdrr.io/r/utils/data.html'>data</a></span><span class='o'>(</span>package <span class='o'>=</span> <span class='s'>"igraphdata"</span><span class='o'>)</span></span></pre>
+<pre class='chroma'>
+<span><span class='c'>#&gt; Data sets in package 'igraphdata':</span></span>
+<span><span class='c'>#&gt; </span></span>
+<span><span class='c'>#&gt; Koenigsberg             Bridges of Koenigsberg from Euler's times</span></span>
+<span><span class='c'>#&gt; UKfaculty               Friendship network of a UK university faculty</span></span>
+<span><span class='c'>#&gt; USairports              US airport network, 2010 December</span></span>
+<span><span class='c'>#&gt; enron                   Enron Email Network</span></span>
+<span><span class='c'>#&gt; foodwebs                A collection of food webs</span></span>
+<span><span class='c'>#&gt; immuno                  Immunoglobulin interaction network</span></span>
+<span><span class='c'>#&gt; karate                  Zachary's karate club network</span></span>
+<span><span class='c'>#&gt; kite                    Krackhardt's kite</span></span>
+<span><span class='c'>#&gt; macaque                 Visuotactile brain areas and connections</span></span>
+<span><span class='c'>#&gt; rfid                    Hospital encounter network data</span></span>
+<span><span class='c'>#&gt; yeast                   Yeast protein interaction network</span></span></pre>
+
+# License
+
+CC BY-SA 4.0, plus see [LICENSE](LICENSE) for the licenses of the individual data sets.