Add column to EditTableDialog to allow setting foreign key constraints

Add a new column to the fiel table in the Edit Table Dialog to allow the
user to add and edit foreign key constraints.

src/EditTableDialog.cpp

@@ -112,6 +112,7 @@ void EditTableDialog::populateFields()
         tbitem->setCheckState(kUnique, f->unique() ? Qt::Checked : Qt::Unchecked);
         tbitem->setText(kDefault, f->defaultValue());
         tbitem->setText(kCheck, f->check());
+        tbitem->setText(kForeignKey, f->foreignKey());
         ui->treeWidget->addTopLevelItem(tbitem);
     }
 
@@ -365,6 +366,11 @@ void EditTableDialog::itemChanged(QTreeWidgetItem *item, int column)
             if(!m_bNewTable)
                 callRenameColumn = true;
             break;
+        case kForeignKey:
+            field->setForeignKey(item->text(column));
+            if(!m_bNewTable)
+                callRenameColumn = true;
+            break;
         }
 
         if(callRenameColumn)

src/EditTableDialog.h

@@ -33,7 +33,8 @@ private:
         kAutoIncrement = 4,
         kUnique = 5,
         kDefault = 6,
-        kCheck = 7
+        kCheck = 7,
+        kForeignKey = 8
     };
 
     void updateColumnWidth();

src/EditTableDialog.ui

@@ -269,6 +269,11 @@
               <string>Check constraint</string>
              </property>
             </column>
+            <column>
+             <property name="text">
+              <string>Foreign Key</string>
+             </property>
+            </column>
            </widget>
            <widget class="QTextEdit" name="sqlTextEdit">
             <property name="readOnly">