Develop (#3)

* Update command added
* Ensure that the upgraded version is really greater
* Update command should not update prerelease
* Minor presentation changes
* Fix command generation in containers from docker-compose file
- Refactored service creation
* Place the full command to the "cmd" package
* Update cobra to v1.4.0
* Updated build and release creation
* Created an install script
* Add more doc
* Add some tests...
* Add a test directive in Makefile

compose/types.go

@@ -36,4 +36,5 @@ type Service struct {
 	EnvFiles    []string          `yaml:"env_file"`
 	RawBuild    interface{}       `yaml:"build"`
 	HealthCheck *HealthCheck      `yaml:"healthcheck"`
+	Command     []string          `yaml:"command"`
 }