Make database install/upgrade provider aware

Ground work for installing and upgrading database schema based upon DB provider (MySQL, PostgresSQL, SQL Server, etc.)

Cleaned up legacy cruft, refactored, commented and made simpler for to support additional database providers.

core/database/db_test.go

@@ -0,0 +1,61 @@
+// Copyright 2016 Documize Inc. <legal@documize.com>. All rights reserved.
+//
+// This software (Documize Community Edition) is licensed under
+// GNU AGPL v3 http://www.gnu.org/licenses/agpl-3.0.en.html
+//
+// You can operate outside the AGPL restrictions by purchasing
+// Documize Enterprise Edition and obtaining a commercial license
+// by contacting <sales@documize.com>.
+//
+// https://documize.com
+
+package database
+
+import (
+	"testing"
+)
+
+// go test github.com/documize/community/core/database -run TestGetVersion
+func TestGetVersion(t *testing.T) {
+	ts2(t, "5.7.10", []int{5, 7, 10})
+	ts2(t, "5.7.10-log", []int{5, 7, 10})
+	ts2(t, "5.7.10-demo", []int{5, 7, 10})
+	ts2(t, "5.7.10-debug", []int{5, 7, 10})
+	ts2(t, "5.7.16-10", []int{5, 7, 16})
+	ts2(t, "5.7.12-0ubuntu0-12.12.3", []int{5, 7, 12})
+	ts2(t, "10.1.20-MariaDB-1~jessie", []int{10, 1, 20})
+	ts2(t, "ubuntu0-12.12.3", []int{0, 0, 0})
+	ts2(t, "junk-string", []int{0, 0, 0})
+	ts2(t, "somethingstring", []int{0, 0, 0})
+}
+
+func ts2(t *testing.T, in string, out []int) {
+	got, _ := GetSQLVersion(in)
+
+	// if err != nil {
+	// 	t.Errorf("Unable to GetSQLVersion %s", err)
+	// }
+
+	for k, v := range got {
+		if v != out[k] {
+			t.Errorf("version input of %s got %d for position %d but expected %d\n", in, v, k, out[k])
+		}
+	}
+}
+
+func TestDatabaseVersionLegacy(t *testing.T) {
+	i := extractVersionNumber("db_00021.sql")
+	if i != 21 {
+		t.Errorf("expected 21 got %d", i)
+	}
+
+	i = extractVersionNumber("db_000.sql")
+	if i != 0 {
+		t.Errorf("expected 0 got %d", i)
+	}
+
+	i = extractVersionNumber("26")
+	if i != 26 {
+		t.Errorf("expected 26 got %d", i)
+	}
+}