Add version package and update the makefile

The makefile will grab the version info from git and pass it to the
linker so that version information based on tags, commits and commit
times is available in the code.

internal/database/manager.go

@@ -14,9 +14,9 @@ import (
 	"strconv"
 
 	_ "github.com/mattn/go-sqlite3"
-)
 
-const expectedSchemaVersion = 1
+	"git.omicron.one/omicron/linkshare/internal/version"
+)
 
 // DB represents a database connection
 type DB struct {
@@ -120,13 +120,13 @@ func (db *DB) CheckSchemaVersion() error {
 	if err != nil {
 		return err
 	}
-	version, err := db.getSchemaVersion()
+	version_, err := db.getSchemaVersion()
 	if err != nil {
 		return err
 	}
-	if version < expectedSchemaVersion {
+	if version_ < version.SchemaVersion {
 		return ErrDatabaseSchemaOutdated
-	} else if version > expectedSchemaVersion {
+	} else if version_ > version.SchemaVersion {
 		return ErrDatabaseSchemaUnsupported
 	}
 	return nil