Add missing include

Author: vgvassilev

src/hyperparams.h

@@ -21,6 +21,8 @@
 #ifndef TUMOR_HYPERPARAMS_H_
 #define TUMOR_HYPERPARAMS_H_
 
+#include "core/real_t.h"
+
 #include <map>
 #include <string>
 
@@ -191,4 +193,4 @@ constexpr real_t kDefaultFractionFluidCartCell = 0.75;
 
 }  // namespace bdm
 
-#endif  // TUMOR_HYPERPARAMS_H_
+#endif  // TUMOR_HYPERPARAMS_H_