Update Travis installation of Nim, as the master branch is defunct

BuildServices.asciidoc

@@ -173,55 +173,61 @@ Same for your code documentation.
 Detailed guide, which the following example originates from: +
 http://blaxpirit.com/blog/22/advanced-uses-of-travis-ci-with-nim.html[Advanced uses of Travis CI with Nim]
 
+https://github.com/oprypin/nim-random/blob/ed21c4a1289d9314901f253e6edce826a794b17e/.travis.yml[Real example]
+
+
 [source,yaml]
 ----
-# Copied from https://github.com/nim-lang/Nim/wiki/TravisCI
 language: c
-env:
-  # Build and test against the master and devel branches of Nim
-  - BRANCH=master
-  - BRANCH=devel
-compiler:
-  # Build and test using both gcc and clang
-  - gcc
-  - clang
+compiler: gcc
 matrix:
+  include:
+    - {}
+    - compiler: clang
+    - env: nim_channel=devel
   allow_failures:
-    # Ignore failures when building against the devel Nim branch
-    - env: BRANCH=devel
+    - env: nim_channel=devel
   fast_finish: true
+before_install:
+  - nim_channel="${nim_channel-stable}"
+  - |
+    if [ "$nim_channel" = stable ]; then
+      nim_branch="v$(curl https://nim-lang.org/channels/stable)"
+    else
+      nim_branch="$nim_channel"
+    fi
 install:
   - |
-    if [ ! -x nim-$BRANCH/bin/nim ]; then
-      git clone -b $BRANCH --depth 1 git://github.com/nim-lang/nim nim-$BRANCH/
-      cd nim-$BRANCH
-      git clone --depth 1 git://github.com/nim-lang/csources csources/
-      cd csources
+    if [ ! -x "nim-$nim_channel/bin/nim" ]; then
+      git clone -b "$nim_branch" https://github.com/nim-lang/nim "nim-$nim_channel/"
+      pushd "nim-$nim_channel"
+      git clone --depth 1 https://github.com/nim-lang/csources csources/
+      pushd csources
       sh build.sh
-      cd ..
+      popd
       rm -rf csources
       bin/nim c koch
       ./koch boot -d:release
     else
-      cd nim-$BRANCH
-      git fetch origin
-      if ! git merge FETCH_HEAD | grep "Already up-to-date"; then
+      pushd "nim-$nim_channel"
+      git fetch origin "$nim_branch"
+      if ! git merge FETCH_HEAD | grep "Already up.to.date"; then
         bin/nim c koch
         ./koch boot -d:release
       fi
     fi
-    cd ..
+    popd
 before_script:
-    - export PATH="nim-$BRANCH/bin${PATH:+:$PATH}"
+    - export PATH="nim-$nim_channel/bin${PATH:+:$PATH}"
 script:
     # Replace uppercase strings!
-    - nim c --cc:$CC --verbosity:0 -r MYFILE.nim
+    - nim compile --cc:$CC --verbosity:0 --run MYFILE.nim
     # Optional: build docs. 
     - nim doc --docSeeSrcUrl:https://github.com/AUTHOR/MYPROJECT/blob/master --project MYFILE.nim
 cache:
   directories:
     - nim-master
-    - nim-devel
+    - nim-stable
 branches:
   except:
     - gh-pages