Added support for database maintenance. Added core plugin.

core/context.h

@@ -2,6 +2,10 @@
 #define CONTEXT_H
 
 #include <QList>
+#include <QMap>
+#include <QString>
+#include <QSqlDatabase>
+
 #include "core_global.h"
 #include "transaction.h"
 
@@ -14,6 +18,7 @@ class CORESHARED_EXPORT Context
 public:
     static Context &instance();
     QList<IPlugin*> plugins();
+    IPlugin *plugin(const QString &pluginId);
     void loadPlugins();
     void openDb(const QString &path);
     odb::database *db() { return m_db; }
@@ -22,6 +27,9 @@ private:
     Context();
     QList<IPlugin*> m_plugins;
     odb::database *m_db;
+
+    void checkDb(const QString &path);
+    void checkSchema(const QSqlDatabase &db, const QMap<QString, int> &schemaMap);
 };
 
 #endif // CONTEXT_H