Merge pull request solidusio#153 from solidusio/reduce_build_matrix

Remove Travis matrix

Author: coorasse

.travis.yml

@@ -7,17 +7,3 @@ before_install:
   - gem install bundler
 rvm:
   - 2.5
-env:
-  matrix:
-    - SOLIDUS_BRANCH=v2.4 DB=postgres
-    - SOLIDUS_BRANCH=v2.5 DB=postgres
-    - SOLIDUS_BRANCH=v2.6 DB=postgres
-    - SOLIDUS_BRANCH=v2.7 DB=postgres
-    - SOLIDUS_BRANCH=v2.8 DB=postgres
-    - SOLIDUS_BRANCH=master DB=postgres
-    - SOLIDUS_BRANCH=v2.4 DB=mysql
-    - SOLIDUS_BRANCH=v2.5 DB=mysql
-    - SOLIDUS_BRANCH=v2.6 DB=mysql
-    - SOLIDUS_BRANCH=v2.7 DB=mysql
-    - SOLIDUS_BRANCH=v2.8 DB=mysql
-    - SOLIDUS_BRANCH=master DB=mysql