absolute link to intro tab in README

README appears on gh and gh-pages. Now it links
correctly from both locations.

README.Rmd

@@ -33,7 +33,7 @@ library(OpenRepGrid)
 
 ## About
 
-**OpenRepGrid** is an R package to analyze and visualize [repertory grid](https://en.wikipedia.org/wiki/Repertory_grid)  data. The repertory grid (often abbreviated *grid* or *repgrid*) is a data collection method which originated from [Personal Construct Theory](https://en.wikipedia.org/wiki/Personal_construct_theory) (Kelly 1955). It was originally designed as an instrument for psychotherapy. Nowadays, it is used in many other fields, including market, organizational, political, educational and sensory research. See tab [Intro](articles/web/intro.html) for a brief introduction. 
+**OpenRepGrid** is an R package to analyze and visualize [repertory grid](https://en.wikipedia.org/wiki/Repertory_grid)  data. The repertory grid (often abbreviated *grid* or *repgrid*) is a data collection method which originated from [Personal Construct Theory](https://en.wikipedia.org/wiki/Personal_construct_theory) (Kelly 1955). It was originally designed as an instrument for psychotherapy. Nowadays, it is used in many other fields, including market, organizational, political, educational and sensory research. See tab [Intro](https://docs.openrepgrid.org/articles/web/intro) for a brief introduction. 
 
 ![**Figure 1.** Example of a repertory grid dataset (with rows and columns clustered by similarity).](man/figures/bertin-clustered.png)
 

README.md

@@ -34,7 +34,8 @@ Theory](https://en.wikipedia.org/wiki/Personal_construct_theory) (Kelly
 1955). It was originally designed as an instrument for psychotherapy.
 Nowadays, it is used in many other fields, including market,
 organizational, political, educational and sensory research. See tab
-[Intro](articles/web/intro.html) for a brief introduction.
+[Intro](https://docs.openrepgrid.org/articles/web/intro) for a brief
+introduction.
 
 <figure>
 <img src="man/figures/bertin-clustered.png"