Adding create community and post buttons from sidebar.

- Fixes #148

ui/src/components/create-post.tsx

@@ -26,7 +26,9 @@ export class CreatePost extends Component<any, any> {
   }
 
   get prevCommunityName(): string {
-    if (this.props.location.state) {
+    if (this.props.match.params.name) {
+      return this.props.match.params.name;
+    } else if (this.props.location.state) {
       let lastLocation = this.props.location.state.prevPath;
       if (lastLocation.includes("/c/")) {
         return lastLocation.split("/c/")[1];

ui/src/components/main.tsx

@@ -136,6 +136,8 @@ export class Main extends Component<any, MainState> {
                     </ul>
                   </div>
                 }
+                <Link class="btn btn-sm btn-secondary btn-block mb-3" 
+                  to="/create_community">Create a Community</Link>
                 {this.sidebar()}
               </div>
             }

ui/src/components/sidebar.tsx

@@ -117,10 +117,12 @@ export class Sidebar extends Component<SidebarProps, SidebarState> {
       </ul>
       <div>
         {community.subscribed 
-          ? <button class="btn btn-sm btn-secondary" onClick={linkEvent(community.id, this.handleUnsubscribe)}>Unsubscribe</button>
+          ? <button class="btn btn-sm btn-secondary btn-block mb-3" onClick={linkEvent(community.id, this.handleUnsubscribe)}>Unsubscribe</button>
-          : <button class="btn btn-sm btn-secondary" onClick={linkEvent(community.id, this.handleSubscribe)}>Subscribe</button>
+          : <button class="btn btn-sm btn-secondary btn-block mb-3" onClick={linkEvent(community.id, this.handleSubscribe)}>Subscribe</button>
         }
       </div>
+      <Link class="btn btn-sm btn-secondary btn-block mb-3" 
+        to={`/create_post/c/${community.name}`}>Create a Post</Link>
       {community.description && 
         <div>
           <hr />

ui/src/index.tsx

@@ -41,6 +41,7 @@ class Index extends Component<any, any> {
             <Route path={`/home/type/:type/sort/:sort/page/:page`} component={Main} />
             <Route exact path={`/`} component={Main} />
             <Route path={`/login`} component={Login} />
+            <Route path={`/create_post/c/:name`} component={CreatePost} />
             <Route path={`/create_post`} component={CreatePost} />
             <Route path={`/create_community`} component={CreateCommunity} />
             <Route path={`/communities/page/:page`} component={Communities} />