Add 4-0-0 branch and released 4.0.0.rc gems to Travis CI build

.travis.yml

@@ -13,6 +13,8 @@ rvm:
 env:
   - ACTIVE_RECORD_BRANCH="master"
   - ACTIVE_RECORD_BRANCH="4-0-stable"
+  - ACTIVE_RECORD_BRANCH="4-0-0"
+  - ACTIVE_RECORD_VERSION="~> 4.0.0.rc2"
   - ACTIVE_RECORD_VERSION="~> 3.2.0"
   - ACTIVE_RECORD_VERSION="~> 3.1.0"
 
@@ -23,23 +25,45 @@ matrix:
     - rvm: jruby-19mode
     - env: ACTIVE_RECORD_BRANCH="master"
     - env: ACTIVE_RECORD_BRANCH="4-0-stable"
+    - env: ACTIVE_RECORD_BRANCH="4-0-0"
+    - env: ACTIVE_RECORD_VERSION="~> 4.0.0.rc2"
+
   exclude:
     - rvm: 1.8.7
       env: ACTIVE_RECORD_BRANCH="master"
     - rvm: 1.8.7
       env: ACTIVE_RECORD_BRANCH="4-0-stable"
+    - rvm: 1.8.7
+      env: ACTIVE_RECORD_BRANCH="4-0-0"
+    - rvm: 1.8.7
+      env: ACTIVE_RECORD_VERSION="~> 4.0.0.rc2"
+
     - rvm: jruby-18mode
       env: ACTIVE_RECORD_BRANCH="master"
     - rvm: jruby-18mode
       env: ACTIVE_RECORD_BRANCH="4-0-stable"
+    - rvm: jruby-18mode
+      env: ACTIVE_RECORD_BRANCH="4-0-0"
+    - rvm: jruby-18mode
+      env: ACTIVE_RECORD_VERSION="~> 4.0.0.rc2"
+
     - rvm: rbx-18mode
       env: ACTIVE_RECORD_BRANCH="master"
     - rvm: rbx-18mode
       env: ACTIVE_RECORD_BRANCH="4-0-stable"
+    - rvm: rbx-18mode
+      env: ACTIVE_RECORD_BRANCH="4-0-0"
+    - rvm: rbx-18mode
+      env: ACTIVE_RECORD_VERSION="~> 4.0.0.rc2"
+
     - rvm: ree
       env: ACTIVE_RECORD_BRANCH="master"
     - rvm: ree
       env: ACTIVE_RECORD_BRANCH="4-0-stable"
+    - rvm: ree
+      env: ACTIVE_RECORD_BRANCH="4-0-0"
+    - rvm: ree
+      env: ACTIVE_RECORD_VERSION="~> 4.0.0.rc2"
 
 before_script:
   - "psql -c 'create database pg_search_test;' -U postgres >/dev/null"