Add Travis CI and pin dependencies (#655)

.travis.yml

@@ -0,0 +1,17 @@
+language: crystal
+
+crystal:
+  - latest
+
+dist: bionic
+
+before_install:
+  - shards update
+  - shards install
+
+install:
+  - crystal build --error-on-warnings src/invidious.cr
+
+script:
+  - crystal tool format --check
+  - crystal spec

README.md

@@ -1,5 +1,7 @@
 # Invidious
 
+[![Build Status](https://travis-ci.org/omarroth/invidious.svg?branch=master)](https://travis-ci.org/omarroth/invidious)
+
 ## Invidious is an alternative front-end to YouTube
 
 - Audio-only mode (and no need to keep window open on mobile)

shard.yml

@@ -11,10 +11,13 @@ targets:
 dependencies:
   pg:
     github: will/crystal-pg
+    version: ~> 0.17.0
   sqlite3:
     github: crystal-lang/crystal-sqlite3
+    version: ~> 0.12.0
   kemal:
     github: kemalcr/kemal
+    version: ~> 0.25.2
 
 crystal: 0.29.0