Custom env vars for apps

Add a table and the install/configure routes. Initially, I thought
we can just keep the env vars in docker container but that doesn't
work since we create the container only later in apptask. And if the
container gets deleted we lose this information.

src/docker.js

@@ -147,6 +147,8 @@ function createSubcontainer(app, name, cmd, options, callback) {
 
         dockerPortBindings[`${containerPort}/${portType}`] = [ { HostIp: '0.0.0.0', HostPort: hostPort + '' } ];
     }
+    let appEnv = [];
+    Object.keys(app.env).forEach(function (name) { appEnv.push(`${name}=${app.env[name]}`); });
 
     // first check db record, then manifest
     var memoryLimit = app.memoryLimit || manifest.memoryLimit || 0;
@@ -177,7 +179,7 @@ function createSubcontainer(app, name, cmd, options, callback) {
             Tty: isAppContainer,
             Image: app.manifest.dockerImage,
             Cmd: (isAppContainer && app.debugMode && app.debugMode.cmd) ? app.debugMode.cmd : cmd,
-            Env: stdEnv.concat(addonEnv).concat(portEnv),
+            Env: stdEnv.concat(addonEnv).concat(portEnv).concat(appEnv),
             ExposedPorts: isAppContainer ? exposedPorts : { },
             Volumes: { // see also ReadonlyRootfs
                 '/tmp': {},